Physics World

An illuminating, if imperfect, celebration of friction

No Author — Fri, 06 Feb 2026 16:30:19 +0000

People who teach physics often remove friction from calculations to make life easier for students. While that might speed up someone’s homework, it does mean that this all-important force tends to fade into the background, despite it being crucial for our daily lives. Here to bring friction centre stage is Jennifer Vail, a “tribologist” – or studier of friction – at US firm TA Instruments.

Friction: a Biography is an engaging and wide-ranging book illustrating its many manifestations in the natural world, showing how this force can be harnessed to solve practical engineering problems. Vail, who wrote the book after giving a hugely popular TED talk on friction, does a great job of connecting abstract physical ideas with familiar human experience.

I like, for example, her description of what happens when two surfaces slide over each other but the friction between them isn’t constant. As she explains, this “stick-slip” motion isn’t great if you’re trying to inject a drug into someone with a syringe. But it can be exploited to beautiful effect by violinists, creating “downright lovely” sounds (though apparently not when she’s practising on her own viola).

One of the book’s strengths is its historical context. Famous figures like Leonardo da Vinci are introduced alongside the development of their ideas, lending a human dimension to the science. The author does a great job of explaining how tribology, which comes from the Greek for “to rub”, has been shaped by careful experimentation and the application of rigorous scientific thinking to industrial problems.

After a trip to Switzerland, the physicist Frank Bowden showed we can ski because frictional heating causes a thin layer of snow to melt beneath our skis, providing liquid lubrication.
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After a trip to Switzerland, for example, the Australian-born physicist Frank Bowden showed we can ski because frictional heating causes a thin layer of snow to melt beneath our skis, providing liquid lubrication. This overturned an earlier explanation associated with Osborne Reynolds (best known for the eponymous number marking the transition from laminar to turbulent flow) who’d thought that snow melts due to pressure.

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Then there is the 19th-century researcher Robert Thurston, whose pendulum experiments on friction in bearings, described here in detail, guided the design of more efficient lubricated systems. As Vail explains, understanding friction is vital in the design of engines, where even small modifications – such as texturing surfaces, adding coatings, or putting nanoparticles into lubricants – can make them much more efficient and extend their useful life.

Historical anecdotes are woven throughout the book. The story of why graphite in pencils came to be called “lead” is particularly memorable. It turns out that the Romans used lead to write, so the name stuck – even after graphite became more popular because it allowed darker writing. There are also lots of excursions into the natural world: did you know that beetles have a protein in their leg joints that acts as a solid lubricant?

Smooth operator

Vail’s discussion of lubrication is clear and well-integrated with practical examples. Particularly insightful is the explanation of how hydrodynamic lubrication occurs in biological systems, such as human cartilage, where a thin fluid layer separates cartilage surfaces in joints, reducing friction and wear. As Vail makes clear, tribology is vital in physiology, for example in how contact lenses work when we blink our eyes or how food feels in our mouth when we chew.

The book also examines fluid dynamics and drag, distinguishing between viscosity as a material property and drag as a force. Vail’s discussion of plaque on the walls of our arteries is particularly compelling. If there’s not enough drag to shear off the plaque it can cause blockages and, potentially, a heart attack – showing how friction plays a role in our health.

Environmental considerations are addressed too. The author discusses, for example, the impact of polytetrafluoroethalyene (PTFE), which she calls “the most controversial solid lubricant ever”. Also known as Teflon, it is widely used in frying pans, but is synthesized using some pretty nasty carcinogenic “forever” chemicals that don’t break down in the environment. PTFE also has a shady past, being first used in the Manhattan atomic-bomb project to coat valves when separating isotopes of uranium.

Friction can improve energy efficiency, reduce greenhouse-gas emissions, and mitigate global warming.
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On a more positive note, Vail shows how an understanding of friction can improve energy efficiency, reduce greenhouse-gas emissions, and mitigate global warming. The book extends further still, encompassing atmospheric, oceanic and planetary processes, as well as astronomy and cosmology. Friction is a universal physical principle, extending well beyond conventional engineering applications and broadening the scope of the book.

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Pockets and pillars capture ricocheting molecules in vacuum pump

Hamish Johnston — Fri, 06 Feb 2026 12:30:43 +0000

The Moon’s polar regions may be less hostile to microbes than previously thought. This is the new finding from researchers at NASA and the University of Maryland in the US who say that future manned missions to the lunar south pole will have to be carefully thought out to limit the unintended transfer of Earth life forms.

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High ultraviolet radiation and temperatures make the Moon’s surface a harsh place and not somewhere bacteria and other microorganisms can easily survive. This is particularly true for the equatorial regions, where all previous crewed missions have been sent. Things might be quite different at the lunar poles, however, since sunlight strikes these high-latitude regions at a low angle because of the Moon’s minimal tilt to the Sun of 1.5 °. The result is long permanent shadows where it is cooler. The moonscape is also as rugged here as elsewhere with mountains and hills, which also cast shadows, and deep craters protected from the Sun’s heat and ultraviolet flux. These conditions allow for water ice too.

Because of these unique properties, future manned missions, such as NASA’s Artemis IV, are scheduled to go to the Moon’s south pole, which has also been identified as a possible future location for a human outpost. The polar regions have already been observed by spacecraft such as ESA’s SMART-1, India’s Chandrayaan, Japan’s Kaguya and NASA’s Lunar Reconnaissance Orbiter. These provided a wealth of information that will be used to prepare future missions.

The problem is that no matter how stringent the sterilization procedures are prior to take-off, the astronauts on these missions will take microbes from Earth with them. Indeed, humans carry millions of microbes on their skin and even more in their bodies.

Landing sites for Artemis IV

To investigate whether microbes could survive in the polar regions, the researchers, led by Prabal Saxena, who works at NASA’s Goddard Space Flight Center, and Stefano Bertone at the University of Maryland, modelled how bacteria and fungi commonly found on human skin would behave in the environment of three candidate landing sites for the upcoming Artemis IV mission. The researchers began by making highly resolved spatial maps of the topography in these regions that included ruggedness, slopes and shadowing effects. They also modelled the UV exposure and temperature in these regions to identify specific locations where microorganisms could survive for at least 24 h.

They obtained seasonal temperature data on length scales of 240 m from measurements by Lunar Reconnaissance Orbiter’s (LRO) Diviner. As for estimated regional UV (≤320 nm) fluxes, these were gleaned from averaged illumination maps with a pixel scale of 60 m based on topography derived from LRO Lunar Orbiter Laser Altimeter (LOLA) measurements.

“Since the temperatures at the lunar poles are rarely high enough to kill bacteria and low temperatures can preserve microbes on Earth, UV radiation is generally likely to be more dangerous in these regions, says Saxena. “We therefore, analysed UV fluxes at finer spatial scales using a technique called ray tracing, and for some regions, included optical effects such as reflection and refraction as sunlight hits the Moon’s surface, leveraging updated LOLA-based topography maps on a scale of 5 m/pixel.”

Understanding how sunlight behaves at the poles, is crucial, he adds. “Since the Moon has a very small axial tilt, the Sun appears to hover just above the horizon here, so even small hills and rocks can prevent light from reaching lower-lying ground, creating small, shadowed areas protected from UV rays.”

Up to seven days survival

The simulations revealed that the bacteria and fungi studied could survive in certain niches for up to or potentially beyond seven days. One particular fungus, the Aspergillus, is particularly resistant to UV radiation and could potentially survive in 15 to 30% of the areas assessed, even those that receive some sunlight during the lunar winter. The reconstructions also showed that all five microbes in this study, Bacillus, Deinococcus, Staphylococcus, Aspergillus and Fusarium could possibly survive in certain areas of the De Gerlache Rim’s permanently shaded regions, including when scattered UV light is incorporated into the simulations.

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Survival does not mean growth (which requires active metabolism and potential reproduction), however, stresses Saxena. Indeed, surviving microbes are in a dormant, so-called cryptobiotic state and would only grow if the conditions were amenable to life – which is not the case for the Moon as we currently understand it.

“Cells may also be dead,” he tells Physics World, “but even dead cells may persist in the environment as another potential source of contamination.”

The work could apply beyond the Moon, he says. Indeed, a number of different airless bodies such as Mercury, Ceres, some asteroids and comets and exoplanets that may have similar properties could also have potential survivable niches for microbial life. Understanding how these niches may exist, how life may be transferred to them and how human exploration may leave its mark will all serve as a key testbed for future potential human exploration of Mars, which likely has far more habitable environments.

“We need to understand what was there before us, because when we search for signs of life beyond our planet on these bodies, we will want to make sure it’s not stuff we brought,” says Saxena.

The research is described in Science Advances.

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Metasurfaces create super-sized neutral atom arrays for quantum computing

Isabelle Dumé — Fri, 06 Feb 2026 09:00:04 +0000

A new way of creating arrays of ultracold neutral atoms could make it possible to build quantum computers with more than 100,000 quantum bits (qubits) – two orders of magnitude higher than today’s best machines. The approach, which was demonstrated by physicists at Columbia University in the US, uses optical metasurfaces to generate the forces required to trap and manipulate the atoms. According to its developers, this method is much more scalable than traditional techniques for generating arrays of atomic qubits.

“Neutral atom arrays have become a leading quantum technology, notably for quantum computing, where single atoms serve as qubits,” explains atomic physicist Sebastian Will, who co-led the study with his Columbia colleague Nanfang Yu. “However, the technology available so far to make these arrays limits array sizes to about 10,000 traps, which corresponds to a maximum of 10,000 atomic qubits.”

Building on a well-established technique

In common with standard ways of constructing atomic qubit arrays, the new method relies on a well-established technique known as optical tweezing. The principle of optical tweezing is that highly focused laser beams generate forces at their focal points that are strong enough to trap individual objects – in this case, atoms.

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To create many such trapping sites while maintaining tight control of the laser’s light field, scientists typically use devices called spatial light modulators (SLMs) and acousto-optic deflectors (AODs) to split a single moderately intense laser beam into many lower-intensity ones. Such arrays have previously been used to trap thousands of atoms at once. In 2025, for example, researchers at the California Institute of Technology in the US created arrays containing up to 6100 trapped atoms – a feat that Will describes as “an amazing achievement”.

A superposition of tens of thousands of flat lenses

In the new work, which is detailed in Nature, Will, Yu and colleagues replaced these SLMs and AODs with flat optical surfaces made up of two-dimensional arrays of nanometre-sized “pixels”. These so-called metasurfaces can be thought of as a superposition of tens of thousands of flat lenses. When a laser beam hits them, it produces tens of thousands of focal points in a unique pattern. And because the pixels in the Columbia team’s metasurfaces are smaller than the wavelength of light they are manipulating (300 nm compared to 520 nm), Yu explains that they can use these metasurfaces to generate tweezer arrays directly, without the need for additional bulky and expensive equipment.

The Columbia researchers demonstrated this by trapping atoms in several highly uniform two-dimensional (2D) patterns, including a square lattice with 1024 trapping sites; patterns shaped like quasicrystals and the Statue of Liberty with hundreds of sites; and a circle made up of atoms spaced less than 1.5 microns apart. They also created a 3.5 mm diameter metasurface that contains more than 100 million pixels and used it to generate a 600 × 600 array of trapping sites. “This is two orders of magnitude beyond the capabilities of current technologies,” Yu says.

Another advantage of using metasurfaces, Will adds, is that they are “extremely resilient” to high laser intensities. “This is what is needed to trap hundreds of thousands of neutral atom qubits,” he explains. “Metasurfaces’ laser power handling capabilities go several orders of magnitude beyond the state of the art with SLMs and AODs.”

Laying the groundwork

For arrays of up to 1000 focal points, the researchers showed that their metasurface-generated arrays can trap single atoms with a high level of control and precision and with high single-atom detection fidelity. This is essential, they say, because it demonstrates that the arrays’ quality is high enough to be useful for quantum computing.

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While they are not there yet, Will says that the metasurface atomic tweezer arrays they developed “lay the critical groundwork for realizing neutral-atom quantum computers that operate with more than 100,000 qubits”. These high numbers, he adds, will be essential for realizing quantum computers that can achieve “quantum advantage” by outperforming classical computers. “The large number of qubits also allows for more ‘redundancy’ in the system to realize highly-efficient quantum error correction codes, which can make quantum computing – which is usually fragile – more resilient,” he says.

The Columbia team is now working on further improving the quality of their metasurfaces. “On the atomic arrays side, we will now try to actually fill such arrays with more than 100 000 atoms,” Will tells Physics World. “Doing this will require a much more powerful laser than we currently have, but it’s in a realistic range.”

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+ Tiny biodegradable stars enhance drug delivery to the skin + https://physicsworld.com/a/tiny-biodegradable-stars-enhance-drug-delivery-to-the-skin/ + Fri, 18 Sep 2026 08:30:34 +0000 + + + + https://physicsworld.com/?p=130422 + Microneedle-coated polymer particles rubbed onto the skin increase the delivery of medication by up to 37-fold

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Physics‑based simulations help diagnose and treat disease

Margaret Harris — Thu, 05 Feb 2026 17:45:43 +0000

Kuwaiti photographer Ali Alobaidly has beaten thousands of amateur and professional photographers from around the world to bag the 2026 Royal Observatory Greenwich’s ZWO Astronomy Photographer of the Year.

The image – The Quiet Predator – captures the Shark Nebula, which lies almost 650 light years away in the constellation Cepheus. The nebula is made of interstellar dust dense enough to block starlight with the blue-coloured areas in the image being “reflection nebulae” – clouds of interstellar dust that do not emit their own visible light but rather scatters and reflects light from nearby stars.

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The image was taken in August 2025 with an Askar 140 APO telescope from the Jahra Governorate, Kuwait.

Sam Wen, founder and chief executive office of the astrophotography firm ZWO, says the image “is a stunning blend of technical excellence and artistic vision”.

“Showcasing the intricate structures of a rarely photographed nebula, the image combines remarkable detail with a striking composition and colour palette, inviting viewers to explore the hidden beauty of the cosmos,” adds Wen.

Alobaidly says it is a “tremendous honour” to receive the award.

“The juxtaposition of an oceanic predator prowling the skies above the Kuwaiti desert is something I find deeply poetic, and it is what first drew me to this remarkable region of the sky,” adds Alobaidly. “To me, it represents perfectly my love for both the Universe and the deserts of my ancestors.”

Alobaidly now hopes to continue using astrophotography for outreach and scientific research.

As well as winning the £10,000 top prize, the image will go on display along with other selected pictures from the competition at an exhibition at the National Maritime Museum observatory on 18 September.

The award – now in its 18th year – is run by the Royal Observatory Greenwich in association with ZWO and BBC Sky at Night Magazine.

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Creating better batteries for electricity grids

Hamish Johnston — Thu, 17 Sep 2026 15:00:58 +0000

This episode of the Physics World Weekly podcast features Amanda Randles, who is a computer scientist and biomedical engineer at Duke University in the US. In a conversation with Physics World’s Margaret Harris, Randles explains how she uses physics-based, computationally intensive simulations to develop new ways to diagnose and treat human disease. She has also investigated how data from wearable devices such as smartwatches can be used identify signs of heart disease.

This episode of the Physics World Weekly podcast features Lin Ma, who is at the University of North Carolina at Chapel Hill. His research group tackles energy and environmental challenges using sustainable materials and electrochemical techniques.

In 2024, the Association for Computing Machinery awarded Randles its ACM Prize in Computing for her groundbreaking work. Harris caught up with Randles at the 2025 Heidelberg Laureate Forum, which brings prizewinning researchers and early-career researchers in computer science and mathematics to Heidelberg, Germany for a week of talks and networking.

Randles began her career as a physicist and she explains why she was drawn to the multidisciplinary research that she does today. Randles talks about her enduring love of computer coding and also reflects on what she might have done differently when starting out in her career.

The post Physics‑based simulations help diagnose and treat disease appeared first on Physics World.

In this episode I chat with Ma about the growing importance of energy storage in electricity grids. Much of this is driven by the growth of wind and solar generation, which can both be intermittent in nature.

Ma talks about the batteries that are currently used in grids and explains what improvements are needed as more renewable energy comes on line. We chat about the different battery technologies that can be used for grid storage and Lin explains why sodium-ion batteries offer advantages over lithium-based devices when it comes to large-scale deployment. Lin also talks about some of the safety issues surrounding large battery facilities and how artificial intelligence can be used to improve many aspects of battery technology.

This podcast is presented in partnership with the Electrochemical Society. The mission of the ECS is to advance theory and practice at the forefront of electrochemical and solid state science and technology, and allied subjects.

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The 10th annual Physics World Careers guide showcases job options for physicists

Matin Durrani — Thu, 05 Feb 2026 16:01:08 +0000

I hear it all the time: physics students have only the haziest idea of what they can do with a physics degree. Staying in academia is the obvious option but they’re often not sure what else is out there. With hefty student debts to pay off, getting a well-paid job in finance seems to top many physicists’ wish lists these days. But there are lots of other options, from healthcare, green energy and computing to education, aviation and construction.

+ Some of the many things you can do with a physics degree are covered in the latest edition of Physics World Careers, which is out now. This bumper, 96-page digital guide contains profiles of physicists working across a variety of fields, along with career-development advice and a directory of employers looking to hire physicists. Now in its 10th year, the guide has become an indispensable source of careers information for physicists setting out in the world of work.

The 2026 edition of Physics World Careers includes, for example, an article featuring two leaders from the UK’s intelligence agency GCHQ, a spotlight on the many jobs in nuclear energy, as well as careers tips from a recent Physics World Live panel. Remember that if you’re ready to start your job search, you can find all the latest opportunities on the Physics World Jobs portal, which has vacancies in physics and engineering for people at all career stages.

A great example of where a physics degree can take you is Rob Farr, a theoretical physicist who’s spent more than 25 years in the food industry. He’s a wonderful illustration of a physicist doing something you might not expect, in his case going from the chilly depths of ice cream science to the dark arts of coffee production and brewing. But that’s the beauty of a physics degree – it provides skills, knowledge and insight that can be applied to very different areas.

Read the latest edition of Physics World Careers by clicking this link.

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Image courtesy: Shutterstock/svekloid

Fancy some more? Check out our puzzles page.

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Joined-up thinking in quantum metrology: why collaboration is the secret of success

No Author — Thu, 05 Feb 2026 11:00:15 +0000

High-level backing “Quantum Metrology: From Foundations to the Future” was held at NPL as part of the global celebrations for the UNESCO International Year of Quantum Science and Technology. Above: Lord Vallance, UK Minister for Science, Innovation, Research and Nuclear, opens the workshop with the official launch of the NMI-Q collaboration, an international metrology initiative that aims to accelerate the adoption of quantum technologies and applications. (Courtesy: NPL)

The UNESCO International Year of Quantum Science and Technology (IYQ) ends on an exotic flourish this month, with the official closing ceremony – which will be live-streamed from Accra, Ghana – looking back on what’s been a global celebration “observed through activities at all levels aimed at increasing public awareness of the importance of quantum science and applications”.

The timing of IYQ has proved apposite, mirroring as it does a notable inflection point within the quantum technology sector. Advances in fundamental quantum science and applied R&D are accelerating on a global scale, harnessing the exotic properties of quantum mechanics – entanglement, tunnelling, superposition and the like – to underpin practical applications in quantum computing and quantum communications.

Quantum metrology, meanwhile, has progressed from its roots in fundamental physics to become a cornerstone of technology innovation, yielding breakthroughs in fields such as precision timing, navigation, cryptography and advanced imaging – and that’s just for starters.

Collaborate to accelerate

Notwithstanding all this forward motion, IYQ has also highlighted significant challenges when it comes to scaling quantum systems, achieving fault tolerance and ensuring reproducible performance. Enter NMI-Q, an international initiative that leverages the combined expertise of the world’s leading National Metrology Institutes (NMIs) – from the G7 countries and Australia – to accelerate the adoption of foundational hardware and software technologies for quantum computing systems and the quantum internet.

Cyrus Larijani “We want NMI-Q to blossom into something much bigger than the individual NMIs.” (Courtesy: NPL)

The NMI-Q partnership was officially launched in November last year at the IYQ conference “Quantum Metrology: From Foundations to the Future”, an event hosted by NPL. Together, the respective NMIs will conduct collaborative pre-standardization research; develop a set of “best measurement practices” needed by industry to fast-track quantum innovation; and, ultimately, shape the global standardization effort in quantum technologies.

“NMI-Q has an ambitious and broad-scope brief, but it’s very much a joined-up effort when it comes to the division of labour,” says Cyrus Larijani, NPL’s head of quantum programme. The rationale being that no one country can do it all when it comes to the performance metrics, benchmarks and standards needed to take quantum breakthroughs out of the laboratory and into the commercial mainstream.

Post-launch, NMI-Q has received a collective “uptick” from the quantum community, with the establishment of internationally recognized standards and trusted benchmarks seen as core building blocks for the at-scale uptake and interoperability of quantum technologies. “What’s more,” adds Larijani, “there’s a clear consensus for collaboration over competition [between the NMIs], supported by shared development roadmaps and open-access platforms to avoid fragmentation and geopolitical barriers.”

Follow the money

In terms of technology push, the scale of investment – both public and private sector – in all things quantum means that the nascent supply chain is evolving at pace, linking component manufacturers, subsystem developers and full-stack quantum computing companies. That’s reinforced by plenty of downstream pull: all sorts of industries – from finance to healthcare, telecoms to energy generation – are seeking to understand the commercial upsides of quantum technologies, but don’t yet have the necessary domain knowledge and skill sets to take full advantage of the opportunities.

Given that context, the onus is on NMI-Q to pool its world-leading expertise in quantum metrology to inform evidence-based decision-making among key stakeholders in the “quantum ecosystem”: investors, policy-makers, manufacturers and, ultimately, the end-users of quantum applications. “Our task is to make sure that quantum technologies are built on reliable, scalable and interoperable foundations,” notes Larijani. “That’s the crux of where we’re going with NMI-Q.”

Made to measure NMI-Q leverages the combined expertise of NMIs from the G7 countries and Australia to shape the global standardization effort in quantum science and technology. Above: NMI-Q representatives gathered at NPL in November for the collaboration’s official launch, announced by UK science minister Lord Vallance (front row, third from right). (Courtesy: NPL)

Right now, NPL and its partner NMIs are busy shaping NMI-Q’s work programme and deliverables for 2026 and beyond, with the benchmarking of quantum computers very much front-and-centre. Their challenge lies in the diversity of quantum hardware platforms in the mix; also the emergence of two different approaches to quantum computing – one being a gate-based framework for universal quantum computation, the other an analogue approach tailored to outperforming classical computers on specific tasks.

“In this start-up phase, it’s all about bringing everyone together to define and assign the granular NMI-Q work packages and associated timelines,” says Larijani. Operational and strategic alignment is also mandatory across the member NMIs, so that each laboratory (and its parent government) is fully on board with the collaboration’s desired outcomes. “It’s going very well so far in terms of aligning members’ national interests versus NMI-Q’s direction of travel,” adds Larijani. “This emphasis on ‘science diplomacy’, if you like, will remain crucial to our success.”

Long term, NMI-Q’s development of widely applicable performance metrics, benchmarks and standards will, it is hoped, enable the quantum technology industry to achieve critical mass on the supply side, with those economies of scale driving down prices and increasing demand.

“Ultimately, though, we want NMI-Q to blossom into something much bigger than the individual NMIs, spanning out to engage the supply chains of member countries,” says Larijani. “It’s really important for NPL and the NMI-Q partners to help quantum companies scale their offerings, advance their technology readiness level and, sooner than later, get innovative products and services into the market.”

That systematic support for innovation and technology translation is evident on the domestic front as well. The UK Quantum Standards Network Pilot – which is being led by NPL – brings together representatives from industry (developers and end-users), academia and government to work on all aspects of standards development and ensure that UK quantum technology companies have access to global supply chains and markets.

Quantum impact

So what does success look like for Larijani in 2026? “We’re really motivated to work with as many quantum companies as we can – to help these organizations launch new quantum products and applications,” he explains. Another aspiration is to encourage industry partners to co-locate their R&D and innovation activities within NPL’s Institute for Quantum Standards and Technology.

“There are moves to establish a quantum technology cluster at NPL to enable UK and overseas companies to access our specialist know-how and unique measurement capability,” Larijani concludes. “Equally, as a centre-of-excellence in quantum science, we can help to scale the UK quantum workforce as well as encourage our own spin-out ventures in quantum metrology.”

Quantum futures: inclusive, ethical, sustainable

“Quantum Metrology: From Foundations to the Future” was held at NPL as part of UNESCO’s IYQ global celebrations. Organized by a steering committee of NMI-Q members, the conference explored quantum metrology and standards as enablers of technology innovation; also their role as “a cornerstone for trust, interoperability, and societal benefit in quantum innovation and adoption”.

The commitments below – articulated as formal recommendations for UNESCO – reflect the collective vision of conference delegates for an inclusive, ethical and sustainable quantum future…

Governance and ethics: attendees emphasized the need for robust governance and ethical oversight in quantum technologies. They called for the establishment of neutral international bodies, ideally under UN leadership, to ensure fair and transparent governance. Inclusivity was highlighted as essential, with a strong focus on extending benefits to developing nations and maintaining open dialogue. Concerns were raised about risks linked to scalability, security and potential misuse by non-state actors, underscoring the importance of proactive monitoring.
Standards and infrastructure: participants advocated for sustained funding to develop international standards and benchmarking frameworks. They also stressed the value of shared fabrication facilities and testbeds to democratize access and accelerate innovation globally.
Education and talent: education and talent development emerged as a priority, with recommendations to launch fully funded MSc programmes, practical placements and mentoring networks. Strengthening links between industry and academia, alongside outreach to schools, are seen as vital for early engagement and long-term skills development.
Societal impact: delegates urged that societal impact remain central to quantum initiatives. Applications in healthcare, climate modelling and sustainability should be a priority; also arts and cultural integration efforts to foster public understanding and ethical reflection.
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Belarusian sculptor unveils artwork honouring US physicist Jim Gates

Michael Banks — Wed, 16 Sep 2026 14:30:35 +0000

Belarusian sculptor Pavel Wilimaytis has created a portrait of the theoretical physicist Jim Gates who is based at the University of Maryland and Brown University.

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Gates is best known for his work on supersymmetry and superstring theory as well as the connections between quantum physics and information theory. He is also known for his outreach in particular the PBS series The Elegant Universe.

Wilimaytis, who has been living in Saint-Jorioz in France for the past three years, has a hearing impairment and chooses people to sculpt based on the “human presence in their faces”.

“For the first eight years of his life, Pavel perceived the world outside of language,” Wilimaytis’ mother Natallia told Physics World. “Before he learned to understand words, he already knew how to feel people: their warmth and coldness, light and shadow, pain, tension, kindness or inner closedness. Not what a person says about themselves, but what emanates from them before any words.”

Wilimaytis noticed photos of Gates online and was struck by the physicist’s “warmth, openness and distinctive charisma”.

“There is the quiet generosity of a scientists and teacher known for his exceptional ability to open the world of knowledge to others,” notes Wilimaytis.

The portrait of Gates, standing around 30 cm tall, was first modelled in plasticine and then cast in Acrystal – a water-based mineral composite material.

The sculpture forms part of Pavel’s sculptural series devoted to figures in science and culture. The series – “The lesser-known faces of famous people” – also includes Nikola Tesla, Marie Curie and Erwin Schrödinger.

In an e-mail to Natallia, Gates noted that he was “absolutely delighted” by the sculpture.

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Schrödinger cat state sets new size record

Isabelle Dumé — Thu, 05 Feb 2026 09:00:57 +0000

Dental work Fitting false teeth, bridges and crowns requires an empirical understanding of how ceramics, metals and other materials interact. (Courtesy: Shutterstock/Ihnatovich Maryia)

My dentist, Dr Albora, told me I needed a new tooth. He made me bite down on a U-shaped tray filled with polyether, an elastomeric material that’s been used in dentistry for decades. I tried not to gag while the gooey stuff set. Albora then waggled it off and sent the imprint to a company on Long Island that makes false teeth. But as my tooth’s colouring was unusual, Dr Albora said I had to go there myself.

A week later I drove to Marotta Dental Studio, where Igor Binshteyn sat me in a chair, lifted my lip and inspected a tooth to the side of my upper jaw. He was helping to fabricate its replacement and needed to get the exact colour.

As Binshteyn finished, I remarked teasingly on the company’s car park, which was chock full. Do you need that many people to make false teeth? What could possibly be involved to make things smaller than the nail on my little finger?

Binshteyn laughed. “Follow me”.

Warm welcome Lenny Marotta (left), who founded Marotta Studio in 1981 and his brother-in-law and Marotta’s vice-president, Steven Pigliacelli in the lab. The flags are for the nationalities and national backgrounds of the 50 or so technicians working there. (Courtesy: Robert P Crease)

He opened a door to a huge undivided warehouse-like space about 1200 square metres in size. Some 50 people were working at lines of tables where the steady hum of conversation was punctuated by the noise of ovens, lathes and grinding machines; imagine the sounds of a metalworking shop in a busy train station.

“Do you want a tour?” Binshteyn said.

Of course I did.

Open wide

My tour guide was Marotta’s vice-president, Steven Pigliacelli, who teaches prosthodontics at New York University. A prosthodontist is a dental specialist who has completed dental school and, in the US, has had at least three additional years of advanced training to focus on restoring and replacing missing or damaged teeth. As I learned, prosthodontists must practice materials science.

The lab has two paths for making teeth, Pigliacelli explained, each with different materials and methods. The first is known as “porcelain-fused-to-metal”, or PFM. It begins with technicians applying gypsum – hydrated calcium sulphate – to create stone replicas of the jaw and teeth from the impressions given to them by dentists such as Albora.

Gypsum has different coefficients of expansion for different dental purposes, and textbook formulas give the amounts of liquid for each kind. But Marotta employees found that tiny amounts of water must be added or subtracted to the gypsum to compensate for things like humidity and temperature before the gypsum is used. “It took us months,” Pigliacelli explained, “to realize that how it’s shipped, how it’s stored, what season it is – all these affect the material.”

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I watched as a technician sectioned a stone jaw replica to cut out a tooth, turn it into a master model called a die, and test it in an articulator that mimics jaw movements. I saw another wax that die, use a lost wax technique to create a solid gypsum frame, and cast a silver-palladium alloy. That creates the metal inner core for the tooth, called a coping, which is shaped and finished before porcelain is applied. Porcelain is baked onto the coping in another area of the lab.

“The metal and porcelain need closely matched coefficients of thermal expansion or the porcelain can separate from the metal,” Pagliacelli told me. “Every once in a while a company tells us ‘We’ve got this really cool new alloy!’, but we need to match the coefficients of expansion in the ceramic material. We’re working with sensitive materials for sensitive applications, and we have to experiment with and adapt them. This stuff about materials you don’t learn in school but work out in the lab.”

Smile for the camera

The second path to making a tooth involves scanning the teeth rather than waxing a die. The electronic files are worked on in the computer, printed out, reworked and rescanned, and milled by a CAD machine using materials such as zirconia – nicknamed “ceramic steel” – and EMAX, a lithium disilicate glass-ceramic. Zirconia is extremely hard and used for teeth that endure heavy grinding forces, while EMAX is more aesthetically pleasing and often used for front teeth.

“So we have two parallel paths, PFM and digital scans”, Pigliacelli said. “It’s usually a personal choice of the dentist”. But external pressures are driving a move away from PFM, he said. Five years ago the price of palladium – a key component of the PFM alloy – soared as it was increasingly used in devices to reduce auto and other emissions. “That’s cut down on the PSM market.”

Say cheese Igor Binshteyn shows off his tooth colour guide. (Courtesy: Robert P Crease)

In another corner of the lab I ran into Binshteyn again, who was using different porcelains and ceramic stains to create colours. “Teeth are not a solid colour,” he said, “but vary in shade from reddish near the gum line to lighter colours toward the biting edge. They also vary in translucency.” (Check this out yourself.) Furthermore, the colour of a tooth must match not its neighbours but the corresponding tooth on the other side of the mouth. To make a natural-looking tooth, Igor picks out a base colour and then layers in shades of porcelain.

As my lab tour went on, Pigliacelli showed me different materials for different applications. One challenge is making teeth for a person with bulimia, whose acidic oral environment can corrode dental materials. Other challenges arise with people who have had failed implants, or temporomandibular joint – or TMJ – a disorder involving jaw joints and muscles.

On the way out I met Lenny Marotta, Pigliacelli’s brother-in-law, who had founded Marotta Studio in 1981. Marotta is fascinated by the history of dental materials, which include bone, ivory, wood, gold and silver. He showed me his collection of early prosthodontic instruments, including milling machines, furnaces, hammers and air compressors.

Later, Marotta also pointed out a strange-looking oven. “That’s for processing vulcanite, a hardened rubber material widely used for dentures before modern plastics.” But he’s been unable to find a museum interested in old prosthodontic stuff. “Nobody knows we exist,” he complained.

The critical point

I’d assumed that materials science was required to make prosthetic teeth biocompatible, corrosion resistant, and able to withstand mechanical motions such as crushing, biting and grinding. I also knew that teeth have to be made economically enough to be widely available, aesthetic enough to be desirable, and versatile enough to withstand a variety of oral environments.

But I had no idea how much materials science was required to bring all these properties together.

Back in his office, Dr Albora installed the tooth and handed me a mirror. I had to pull up my lip to see it way on the side of my mouth. “I’d have to smile before somebody notices it,” I complained. “Well,” he said, “that’s for just in case you do.”

The post Get your teeth into the cutting edge of materials science appeared first on Physics World.

Using AI boosts scientific productivity and career prospects, finds study

No Author — Wed, 04 Feb 2026 15:00:07 +0000

(Courtesy: Shutterstock/PeopleImages)

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Join us for an in-depth conversation with Xiaochuan Pan as he shares an expert perspective on the rapidly evolving landscape of advanced X-ray imaging—highlighting the breakthroughs shaping the field, what defines high-impact research, and how Physics in Medicine & Biology supports and amplifies this work. He will also explore what sets outstanding early-career research apart and offer practical strategies for increasing the visibility, reach, and long-term impact of your publications.

This session will also spotlight the research of Ronan Smith, winner of the 2025 PMB Early Career Award, who will reflect on his contributions to advanced X-ray imaging—including his award-winning paper—and how his work connects to wider developments in medical physics and imaging.

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Left to right: Carol Clark, Xiaochuan Pan, Ronan Smith

Moderator

Carol Clark, Publisher, Physics in Medicine & Biology

Speakers

Xiaochuan Pan is Professor of Radiology, Radiation & Cellular Oncology, Committee in Medical Physics, the College, and the University of Chicago Medicine Comprehensive Cancer Center at The University of Chicago. His research centers on physics, algorithms, and engineering underpinning tomographic imaging and its biomedical and clinical applications. He has made pioneering, significant contributions to advanced theory and algorithms for conventional and spectral computed tomography (CT), positron emission tomography (PET), and single-photo-emission computed tomography (SPECT). He has contributed to algorithm development for digital breast tomosynthesis (DBT), digital lung tomosynthesis (DLT), magnetic resonance imaging (MRI), electron-paramagnetic resonance imaging (EPRI), phase-contrast CT, and photo-acoustic tomography (PAT). He has also developed strong translational imaging technological programs tailored to specific applications of biomedical and/or clinical significance. Xiaochuan is a Fellow of AAPM, AIMBE, IAMBE, IEEE, OSA, NAI, and SPIE.

Ronan Smith is a physicist interested in better ways of X-ray imaging. He completed his PhD at Southampton University (UK) in 2023, developing a technique called dark-field X-ray imaging, before moving to the warmer climate of Adelaide University in Australia as a grant-funded researcher in the School of Medicine. He focuses on developing and implementing imaging techniques for challenging and dynamic environments, such as the respiratory system. His current area of research is novel ways of analysing and understanding a new method for dynamic lung imaging called X-ray Velocimetry, with side projects looking at dark-field X-ray imaging.

About this journal
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Physics in Medicine & Biology. The international journal of biomedical physics and engineering, published by IOP Publishing on behalf of the Institute of Physics and Engineering in Medicine (IPEM)

Editor-in-chief: Katia Parodi, Ludwig-Maximilians University, Munich, Germany

The post Establishing a research career in advanced X-ray Imaging: insights from Xiaochuan Pan and PMB award winner Ronan Smith appeared first on Physics World.

Interactions between dark matter and neutrinos could resolve a cosmic discrepancy

Isabelle Dumé — Wed, 04 Feb 2026 13:00:45 +0000

Hints of non-gravitational interactions between dark matter and “relic” neutrinos in the early universe have emerged in a study of astronomical data from different periods of cosmic history. The study was carried out by cosmologists in Poland, the UK and China, and team leader Sebastian Trojanowski of Poland’s NCBJ and NCAC PAS notes that future telescope observations could verify or disprove these hints of a deep connection between dark matter and neutrinos.

Dark matter and neutrinos play major roles in the evolution of cosmic structures, but they are among the universe’s least-understood components. Dark matter is thought to make up over 25% of the universe’s mass, but it has never been detected directly; instead, its existence is inferred from its gravitational interactions. Neutrinos, for their part, are fundamental subatomic particles that have a very low mass and interact only rarely with normal matter.

Analysing data from different epochs

According to the standard (ΛCDM) model of cosmology, dark matter and neutrinos do not interact with each other. The work of Trojanowski and colleagues challenges this model by proposing that dark matter and neutrinos may have interacted in the past, when the universe was younger and contained many more neutrinos than it does today.

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This proposal, they say, was partly inspired by a longstanding cosmic conundrum. Measurements of the early universe suggest that structures such as galaxies should have grown more rapidly than ΛCDM predicts. At the same time, observations of today’s universe indicate that matter is slightly less densely packed than expected. This suggests a slight mismatch between early and late measurements.

To explore the impact that dark matter-neutrino interactions (νDM) would have on this mismatch, a team led by Trojanowski’s colleague Lei Zu analysed data from different epochs of the universe’s evolution. Data from the young (high redshift) universe came from two instruments – the ground-based Atacama Cosmology Telescope and the space-based Planck Telescope, which the European Space Agency operated from 2009 to 2013 – that were designed to study the afterglow of the Big Bang, which is known as the cosmic microwave background (CMB). Data from the older (low-redshift, or z< 3.5) universe, meanwhile, came from a variety of sources, including galaxy maps from the Sloan Digital Sky Survey and weak gravitational lensing data from the Dark Energy Survey (DES) conducted with the Dark Energy Camera on the Victor M Blanco Telescope in Chile.

“New insight into how structure formed in the universe”

Drawing on these data, the team calculated that an interaction strength u ≈10⁻⁴ between dark matter and neutrinos would be enough to resolve the discrepancy. The statistical significance of this result is nearly 3σ, which team member Sming Tsai Yue-Lin of the Purple Mountain Observatory in Nanjing, China says was “largely achieved by incorporating the high-precision weak lensing data from the DES with the weak lensing component”.

While this is not high enough to definitively disprove the ΛCDM model, the researchers say it does show that the model is incomplete and requires further investigation. “Our study shows that interactions between dark matter and neutrinos could help explain this difference, offering new insight into how structure formed in the universe,” explains team member Eleonora Di Valentino, a senior research fellow at Sheffield University, UK.

Trojanowski adds that the ΛCDM has been under growing pressure in recent years, while the Standard Model of particle physics cannot explain the nature of dark matter. “These two theories need to be extended to resolve these problems and studying dark matter-neutrino interactions are a promising way to achieve this goal,” he says.

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The team’s result, he continues, adds to the “massive amount of data” suggesting that we are reaching the limits of the standard cosmological model and may be at the dawn of understanding physics beyond it. “We illustrate that we likely need to bridge cosmological data and fundamental particle physics to describe the universe across different scales and so resolve current anomalies,” he says.

Two worlds

One of the challenges of doing this, Trojanowski adds, is that the two fields involved – cosmological data analysis and theoretical astroparticle physics – are very different. “Each field has its own approach to problem-solving and even its own jargon,” he says. “Fortunately, we had a great team and working together was really fun.”

The researchers say that data from future telescope observations, such as those from the Vera C Rubin Observatory (formerly known as the Large Synoptic Survey Telescope, LSST) and the China Space Station Telescope (CSST), could place more stringent tests on their hypothesis. Data from CMB experiments and weak lensing surveys, which map the distribution of mass in the universe by analysing how distant galaxies distort light, could also come in useful.

They detail their present research in Nature Astronomy.

The post Interactions between dark matter and neutrinos could resolve a cosmic discrepancy appeared first on Physics World.

+ Fast 3D imaging reveals how seizures move through the brain + https://physicsworld.com/a/fast-3d-imaging-reveals-how-seizures-move-through-the-brain/ + Wed, 16 Sep 2026 08:30:14 +0000 + + + + + https://physicsworld.com/?p=130403 + A high-speed, 3D light-sheet microscope allows researchers to record seizure dynamics in larval zebrafish

The post Fast 3D imaging reveals how seizures move through the brain appeared first on Physics World.

Forecasting future demand on the Texas grid

Lorna Brigham — Wed, 16 Sep 2026 07:57:15 +0000

In Texas, US, electricity demand is expected to grow because of rapid population growth, increased adoption of electric vehicles, expansion of AI data centres, and other societal and industrial developments. Most of Texas’ electricity system is managed by the Electric Reliability Council of Texas (ERCOT), which operates a grid that is largely independent from the rest of the United States. Combined with the state’s rapidly changing demand patterns, this makes Texas an important test case for exploring future energy scenarios.

In this work, the researchers developed a framework to model how different sources of electricity demand growth could affect the Texas grid through to 2050. They separately examined the impacts of population growth, electrified heating, electric vehicles, large industrial loads such as data centres, and electrification of oil and gas operations.

The study found that electric vehicles have the greatest impact on peak electricity demand because charging tends to occur at similar times of day, creating sharp increases in demand. In contrast, large industrial loads, including data centres, cryptocurrency mining, hydrogen production and manufacturing facilities, have the greatest impact on overall electricity consumption because they often operate continuously. Electrification of heating had a smaller net effect because heat pumps increase winter electricity demand while simultaneously reducing summer electricity demand through more efficient cooling.

The findings suggest that different types of demand growth require different grid solutions. Battery storage is particularly effective for managing the sharp demand peaks associated with electric vehicle charging, whereas growth from data centres and other large industrial loads is most economically met through additional natural gas, wind and solar generation. The study also showed that uncertainty in future demand could lead to dramatically different grid expansion requirements by 2050.

A key impact of this work is demonstrating that the source of future electricity demand can be just as important as its size, since different demand drivers require different investments in generation, storage and grid infrastructure. The framework developed in this study could help planners, investors and policymakers make more informed decisions about future electricity systems.

Read the full article

A method to assess the energy impacts of meeting ERCOT’s uncertain future electricity demand

Drew A Kassel et al 2026 Prog. Energy 8 035001

Do you want to learn more about this topic?

How different power plant types contribute to electric grid reliability, resilience, and vulnerability: a comparative analytical framework by K Ramirez-Meyers et al. (2021)

The post Forecasting future demand on the Texas grid appeared first on Physics World.

Quantum states that won’t entangle

Paul Mabey — Wed, 04 Feb 2026 10:20:29 +0000

Quantum entanglement is a uniquely quantum link between particles that makes their properties inseparable. It underlies the power of many quantum technologies from secure communication to quantum computing, by enabling correlations impossible in classical physics.

Entanglement nevertheless remains poorly understood and is therefore the subject of a lot of research, both in the fields of quantum technologies as well as fundamental physics.

In this context, the idea of separability refers to a composite system that can be written as a simple product (or mixture of products) of the states of its individual parts. This implies there is no entanglement between them and to create entanglement, a global transformation is needed.

A system that remains completely free of entanglement, even after any possible global invertible transformation is applied, is called absolutely separable. In other words, it can never become entangled under the action of quantum gates.

Separable, Absolutely Separable and Entangled sets: It is impossible to make absolutely separable states entangled with a global transformation (Courtesy J. Abellanet Vidal and A. Sanpera Trigueros)

Necessary and sufficient conditions to ensure separability exist only in the simplest cases or for highly restricted families of states. In fact, entanglement verification and quantification is known to be generically an NP-hard problem.

Recent research published by a team of researchers from Spain and Poland has tackled this problem head-on. By introducing new analytical tools such as linear maps and their inverses, they were able to identify when a quantum state is guaranteed to be absolutely separable.

These tools work in any number of dimensions and allow the authors to pinpoint specific states that are on the border of being absolutely separable or not (mathematically speaking, ones that lie on the boundary of the set). They also show how different criteria for absolute separability, which may not always agree with each other, can be combined and refined using convex geometry optimisation.

Being able to more easily and accurately determine whether a quantum state is absolutely separable will be invaluable in quantum computation and communication.

The team’s results for multipartite systems (systems with more than two parts) also reveal how little we currently understand about the entanglement properties of mixed, noisy states. This knowledge gap suggests that much more research is needed in this area.

+ https://physicsworld.com/?p=129465 + A defect framework unlocks difficult calculations in N = 4 super Yang-Mills

The post A new way to study giant gravitons appeared first on Physics World.

The secret limits governing quantum relaxation

Paul Mabey — Wed, 04 Feb 2026 09:56:27 +0000

Material behaviour is traditionally determined by chemistry. Free electrons in metals give rise to conductivity, unfilled orbitals make elements reactive. Metamaterials, on the other hand, have properties that come mainly from its internal design, not just from what it is made of.

These types of materials are characterised by a specifically designed larger-scale repeating pattern that interacts with waves in a chosen way. Invisibility cloaks are one such example. These are designed so that waves bend around an object and then recombine on the other side, making the object scatter much less light, sound or another type of wave.

The challenge is designing metamaterials to give you exactly the properties that you want. Two equations come into play.

The Laplace equation. This describes steady-state conditions with no oscillations or waves and has only one free parameter. It is easy to use but the metamaterial properties you can get are often limited.
The Helmholtz equation. This describes oscillations – sound waves, light waves etc. To use this equation, the wave medium usually needs two material parameters. For acoustics, these are equivalent to mass density and bulk modulus, which together determine how sound travels. Harder to work with, but more powerful.

The goal of new research from a team of researchers from China and Singapore is to have the best of both worlds. They were able to develop a mathematical correspondence between these two equations and use it to design metamaterials with new properties. Counterintuitively, they found that less complicated designs can achieve more. This less-for-more approach doesn’t try to design every aspect of how a wave behaves, but instead starts with a simpler, more manageable problem to access a wide range of useful effects.

The team used acoustics as testbed to demonstrate the power of their work. They demonstrated a range of novel phenomena such as three-dimensional freeform conformal cloaking, an experimentally validated waveguide cloak and the hyperbolic invisibility mentioned earlier. Because the technique is based on equations shared by several types of waves, their approach could also be applied to water waves and electromagnetic waves. This makes it a broadly transferable strategy for designing metamaterials

Real devices will still face practical limits from losses, dispersion and the need to approximate continuous material properties with fabricated structures. However, this new work does offer a practical method to design new metamaterials with exotic properties, and to manipulate waves beyond conventional constraints.

Read the full article

A universal constraint for relaxation rates for quantum Markov generators: complete positivity and beyond – IOPscience

D. Chruściński et al, 2025 Rep. Prog. Phys. 88 097602

A less-for-more metamaterial paradigm via Laplace-Helmholtz correspondence – IOPscience

Z. Guo et al 2026 Rep. Prog. Phys. 89 077501

The post The secret limits governing quantum relaxation appeared first on Physics World.

The post How do you design an invisibility cloak? appeared first on Physics World.

Implanted electrodes provide intuitive control of prosthetic hand

Tami Freeman — Wed, 04 Feb 2026 09:00:49 +0000

Maxim Simmonds measuring perovskite solar mini module samples with Solira. (Courtesy: PicoQuant)

When evaluating new materials for optoelectronic applications – perhaps promising solar panel materials like halide perovskites or semiconductor compounds for microLED displays – optical characterization is almost always the materials scientists’ first port of call. And up to now steady-state photoluminescence (PL) has been the de facto workhorse for this task.

This non-destructive and highly sensitive technique involves optically exciting a sample and recording the integrated intensity and wavelength of re-emitted photons. Through this, researchers gain a quick understanding into a material’s electronic structure, optical transitions and emission characteristics.

However, these spectra alone can be misleading. Materials with substantially different microscopic properties can generate similar steady-state PL results, masking the fundamental physical dynamics that govern the material’s performance in the real world. To gain deeper understanding of a given material, a more comprehensive and correlated approach is needed.

Blinding average

The core issue lies in the fact that steady-state PL provides a time-integrated view of the emission and depending on the measurement geometry, may also average over spatial variations. Steady-state PL records a static equilibrium in which charge carrier generation balances recombination. This means that, on its own, it does not directly reveal how these excited charge-carriers evolve and ultimately dictate how a device manipulates energy and light.

For example, although two semiconductor thin films may show identical steady-state emission, they can perform very differently in a real device. One film might have long carrier lifetimes consistent with low non-radiative losses – useful in solar cells, for example – while the other could suffer from high defect densities that are masked by strong light absorption or intense excitation light.

Conversely, weak emission does not necessarily mean poor material quality. Again using a layered solar cell as an example, dim luminescence often signals fast, beneficial charge extraction across an interface rather than harmful defect recombination (where structural imperfections convert charge-carrier energy into wasted heat). Because steady-state measurements only show an overall average, they cannot separate these competing mechanisms.

Resolving in time, space and spectrum

Time-resolved PL (TRPL) is a key technique in illuminating these hidden dynamics. Unlike steady-state PL, which continuously bathes a sample with light, TRPL uses a short laser pulse and measures how the photoluminescence intensity evolves afterwards. This can reveal carrier dynamics over timescales ranging from picoseconds to microseconds.

TRPL is particularly important in materials where local variations strongly influence device behaviour. For instance, it can expose the difference between regions that exhibit long-lived emission consistent with efficient radiative recombination, and those that exhibit fast decay caused by, for example, defect recombination.

Of course, steady-state PL averages over time and space, and therefore TRPL only solves part of the problem. Spatially resolved TRPL addresses the missing spatial dimension. Combining a high-precision, motorized XY stage with TRPL’s precise timing, spatially resolved TRPL forms a 2D map that directly correlates localized structural features – such as grain boundaries and defects – with variations in carrier kinetics across the surface.

Complementary to these techniques is time-resolved emission spectroscopy (TRES), which combines spectral selection with time-resolved detection to measure how emission dynamics vary across the spectrum. By recording wavelength-dependent decay behaviour, TRES reveals how different spectral contributions evolve following excitation.

In short, where TRPL reveals kinetics over time and spatially resolved TRPL locates variations in space, TRES adds a spectral dimension, showing how the emission spectrum evolves after excitation. This allows researchers to track changes in the distribution of photon energies over time to understand carrier evolution and gain insight into the mechanisms underlying material behaviour.

A correlative approach

Though powerful in isolation, reconciling insights across these different instruments is slow and prone to errors. There can be microscopic differences between samples or even within positions in a single sample that dramatically alter emission spectra. Moreover, moving a sample between separate instruments is fraught with difficulty, potentially damaging the sample or causing delays that lead to sample degradation.

PicoQuant’s Solira, an all-in-one time-resolved photoluminescence microscope for flexible optical characterization of materials and optoelectronic devices. (Courtesy: PicoQuant)

More comprehensive and reliable physical insight comes when temporal, spatial and spectral factors are recorded correlatively on the exact same sample region. This need for correlation is the motivation behind PicoQuant’s Solira, an integrated workflow platform for steady-state PL, TRPL, spatially resolved TRPL and TRES (the latter when combined with the complementary FlexLambda Kit), as well as additional imaging techniques, such as hyperspectral imaging, required for different scientific questions.

Bringing these techniques together within one configurable microscope system means a materials scientist can gain a more informed interpretation of material behaviour. For instance, they can identify the relevant emission bands at selected points of interest with steady-state PL. They can then wield TRPL to measure the associated decay kinetics, before perhaps applying TRES to resolve how those kinetics vary across the emission spectrum.

TRPL decay curves recorded at positions close to and away from a laser-patterned region of a perovskite solar mini module sample. The decay measured adjacent to the structured line exhibits faster PL decay dynamics compared to the unmodified region farther from the laser-patterned area. (Courtesy: PicoQuant)

Bright demonstration

The power of this correlated approach was demonstrated recently by Professor Eva Unger’s group at Helmholtz-Zentrum Berlin, Germany, with measurements carried out by Maxim Simmonds. Investigating perovskite solar mini-modules, the team worked with PicoQuant and used Solira to locate precise laser-patterned lines – microscopic scribes used to interconnect individual cells in a solar module – before verifying emission from the active layer. Localized TRPL measurements then revealed significantly faster decay dynamics next to these laser cuts compared to the pristine bulk material, indicating altered carrier recombination or diffusion near structured features.

Spatially resolved TRPL image recorded from a sample of a perovskite solar mini module, showing photoluminescence lifetime differences between laser-patterned lines and bulk material. The structured regions remain photoluminescent, indicating that the laser process modifies local photophysical properties rather than completely removing the emissive material. (Courtesy: PicoQuant)

However, point measurements alone were not enough to discern whether the laser had fully removed the perovskite or merely modified it. Switching to spatially resolved TRPL imaging on Solira revealed that measurable photoluminescence persisted along the laser-patterned lines. This showed that laser structuring had altered local photophysical properties rather than eliminating the active layer – a conclusion only made possible by consistently mapping charge-carrier dynamics across temporal, spatial and spectral dimensions together on one setup.

As semiconductor materials and optoelectronic devices become more complex, optical characterization tools must keep pace. By unifying these tools within an integrated workflow platform such as Solira, materials scientists now have the means to paint a more complete picture of material characteristics and thereby unlock the next generation of innovative functional materials.

The post Above-average correlative materials characterization appeared first on Physics World.

‘Vacuumtronics’ could help make better superconductors

Isabelle Dumé — Tue, 15 Sep 2026 11:00:32 +0000

Vacuum fluctuations can enhance superconductivity in a bulk material. This is the new finding from researchers in China and the US who have put forward the concept of “vacuumtronics”. This is a new way to tune superconductivity without chemically altering a material, applying pressure to it or driving it with intense light.

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In quantum electrodynamics, a vacuum is not empty but is host to fluctuating electromagnetic fields in which pairs of virtual particles are continuously being created and annihilated. Such vacuum fluctuations are thought to be responsible for phenomena like the Lamb shift, spontaneous emission and the Casimir effect.

In recent years researchers have been looking into the possibility of exploiting these fluctuations to change the properties of bulk matter. This is challenging because the fluctuations are extremely weak and produce little measurable change in macroscopic quantum states. They can, however, be amplified by a factor of 100 or even more using structures like resonant cavities. Indeed, such enhanced vacuum fields have already been exploited to modify material properties like chemical reactivity, topological states and conductivity.

In theory, vacuum fluctuations could be used to modulate superconductivity too, but until now this had never been demonstrated in an experiment.

Split-ring resonant “dark cavity”

In the new work, an experimental team led by Changgan Zeng and Guanghui Cheng at the University of Science and Technology of China (USTC), partially embedded the layered superconductor niobium diselenide (NbSe₂) inside a specially designed near-terahertz split-ring resonator, referred to as a “dark cavity”. The researchers then systematically compared the superconductivity of the NbSe₂ outside and inside the cavity by measuring the resistance of the material as a function of temperature.

They found an increase of up to 5.4% in the superconducting critical temperature, T_c, of NbSe₂ within the cavity compared with regions outside it, even although both samples came from the same NbSe₂ flake.

Higher current and field

The researchers say they also observed substantial increases in the critical current and critical magnetic field near T_c. This is exciting, says Cheng, because the cavity is dark: no light shines on the material and no energy is actively pumped into it. “Instead, the effect arises from the ever-present electromagnetic fluctuations of the quantum vacuum.”

One of the challenges in the experiments, he explains, was to distinguish between genuine vacuum-fluctuation effects from more mundane explanations, such as sample inhomogeneity, strain or device fabrication-related effects. He says he and his colleagues invested considerable effort in control experiments to rule these out.

Zheng and Cheng’s theorist colleagues Qingdong Jiang from Shanghai Jiao Tong University and Frank Wilczek from the Massachusetts Institute of Technology (MIT) department of physics developed a theoretical model to explain the underlying mechanism behind the effects observed. Within a Ginzburg–Landau framework, they put forward the hypothesis that the superconducting state exchanges virtual photons with the dark cavity, which lowers the energy of this state and thereby strengthens superconductivity. And, when the characteristic energy of the cavity mode matches the low-energy superconducting fluctuations, the NbSe₂ device exhibits resonant enhancement, producing the peak in superconductivity enhancement, explains Jiang.

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Wilczek adds “In most practical physics experiments, the vacuum serves merely as the passive stage on which such phenomena play out”. “Our work shows that the background itself can become an actor – engineered to strengthen superconductivity and reshape the behaviour of quantum matter.”

The work establishes quantum-vacuum engineering as a new non-invasive way to tune superconductivity, Zeng tells Physics World. “Although the temperature enhancement we demonstrated is modest, it is a proof-of-principle for what could become a broadly applicable approach. It could be relevant to superconducting circuits, quantum sensors and other quantum devices, where non-invasive control of superconducting properties would be particularly valuable. More broadly, such engineered vacuum fields could also be used to control states of matter other than superconductivity.”

The China–US team says it would now like to further enhance the effect through improved cavity and material design and continue to investigate the underlying microscopic mechanisms in collaboration with theorists.

The post ‘Vacuumtronics’ could help make better superconductors appeared first on Physics World.

New cosmic map will put dark-matter theories to the test

No Author — Tue, 03 Feb 2026 15:22:40 +0000

Astronomers have created the most detailed map to date of the vast structures of dark matter that appear to permeate the universe. Using the James Webb Space Telescope (JWST), the team, led by Diana Scognamiglio at NASA’s Jet Propulsion Laboratory, used gravitational lensing to map the dark matter filaments and clusters with unprecedented resolution. As a result, physicists have new and robust data to test theories of dark matter.

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Dark matter is a hypothetical substance that appears to account for about 85% of the mass in universe – yet it has never been observed directly. Dark matter is invoked by physicists to explain the dynamics and evolution of large scale structures in the universe. This includes the gravitational formation of galaxy clusters and the cosmic filaments connecting them over 100-million-light–year distances.

Light from very distant objects beyond these structures is deflected by the gravitational tug of dark matter within the clusters and filaments. This can be observed on Earth as the gravitational lensing of these distant objects. This distorts images of the distant objects and affects their observed brightness. These effects can be used to determine the dark-matter content of the clusters and filaments.

In 2007, the Cosmic Evolution Survey (COSMOS) used the Hubble Space Telescope to create a map of cosmic filaments in an area of the sky about nine times larger than that occupied by the Moon.

“The COSMOS field was published by Richard Massey and my advisor, Jason Rhodes,” Scognamiglio recounts. “It has a special place in the history of dark-matter mapping, with the first wide-area map of space-based weak lensing mass.”

However, Hubble’s limited resolution meant that many smaller-scale features remained invisible in COSMOS. In a new survey called COSMOS-Web, Scognamiglio’s team harnessed the vastly improved imaging capabilities of the JWST, which offers over twice the resolution of its predecessor.

Sharp and sensitive

“We used JWST’s exceptional sharpness and sensitivity to measure the shapes of many more faint, distant galaxies in the COSMOS-Web field – the central part of the original COSMOS field,” Scognamiglio describes. “This allowed us to push weak gravitational lensing into a new regime, producing a much sharper and more detailed mass map over a contiguous area.”

With these improvements, the team could measure the shapes of 129 galaxies per square arcminute in area of sky the size of 2.5 full moons. With thorough mathematical analysis, they could then identify which of these galaxies had been distorted by dark-matter lensing.

“The map revealed fine structure in the cosmic web, including filaments and mass concentrations that were not visible in previous space-based maps,” Scognamiglio says.

Peak star formation

The map allowed the team to identify lensing structures out to distances of roughly 5 billion light–years, corresponding to the universe’s peak era of star formation. Beyond this point, galaxies became too sparse and dim for their shapes to be measured reliably, placing a new limit on the COSMOS-Web map’s resolution.

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With this unprecedented resolution, the team could also identify features as small as the dark matter halos encircling small clusters of galaxies, which were invisible in the original COSMOS survey. The astronomers hope their result will set a new, higher-resolution benchmark for future studies using JWST’s observations to probe the elusive nature of dark matter, and its intrinsic connection with the formation and evolution of the universe’s largest structures.

“It also sets the stage for current and future missions like ESA’s Euclid and NASA’s Nancy Grace Roman Space Telescope, which will extend similar dark matter mapping techniques to much larger areas of the sky,” Scognamiglio says.

The observations are described in Nature Astronomy.

The post New cosmic map will put dark-matter theories to the test appeared first on Physics World.

+ https://physicsworld.com/?p=130360 + While energy usage could be met, water would cause some issues

The post Moon’s water reserves insufficient to sustain a lunar city, astronomers find appeared first on Physics World.

Could quantum information theory explain universe evolution?

Sam Jones — Mon, 14 Sep 2026 11:18:12 +0000

The gravity from entropy (GfE) theory has been used to explain how low-entropy structures such as galaxies emerge and endure in a universe in which entropy increases with time. Using the theory, Ginestra Bianconi of the UK’s Queen Mary University of London has shown how entropy density can decrease locally, while the total entropy of the universe increases.

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The laws of thermodynamics are arguably among the most fundamental principles in most areas of physics. Perhaps none more so than the second law of thermodynamics, which states that the entropy of a system must increase over time. Uniquely, it is the only law of physics that captures the direction of time we experience.

Fundamentally, entropy is a measure of disorder: lower entropy means more structure and higher entropy means a less structured system. Increasing entropy is the reason diffusion occurs from a high concentration to a low concentration, gases expand, and coffee goes cold.

Cosmological paradox

It is believed that the evolution of the universe also follows the second law. The early universe was in a state of low entropy, and it has evolved to states of high entropy. It is also true that during this evolution, the universe has given rise to some incredibly complex structures. Galaxies are a prime example of one of these structures, which are low in entropy but have formed in a high-entropy environment. Their creation seemingly violates the second law. This is a longstanding contradiction in the field of cosmology that is motivating the gravitational framework proposed by Bianconi.

In a recent paper called “Thermodynamics of the gravity from entropy theory”, Bianconi, built on her previous work on the GfE theory and applied it to the whole universe to tackle this challenging paradox.

In Einstein’s general theory of relativity, the metric mathematically describes how the space–time of a universe is curved. Mass follows this curvature, and this is how a gravitational force is realized. In quantum mechanics, operators are mathematical objects that can be applied to physical quantum states to transform them (for example the time evolution or reflection of a quantum state).

Quantum relative entropy

The key insight of the GfE theory is that these metrics are treated as quantum operators which encode the geometry of space–time. Quantizing the geometry of space–time in this manner leads to two notions of the metric – one that is the “true” metric, and one that is induced via mass and energy. The distinguishability between the true manifold metric and one that is induced from the mass, and energy is measured by a quantity rooted in quantum information theory, called quantum relative entropy (QRE). It is this interplay between the two geometries measured through QRE that, in this scenario, defines the dynamics of the space–time.

In other words, the QRE leads to equations of motion that describe gravity. Bianconi found that in the low curvature limit, classical general relativity is reproduced exactly from these equations. However, outside of this limit, the equations must be modified by a mathematical object called the ‘G-field’. This G-field generates a dark-energy term that is surprisingly dynamical. Dark energy is thought to drive the universe’s expansion directly. In standard general relativity, dark energy is driven by the static cosmological constant, which is why a surprising dynamical dark energy term from the G-field is an avenue that has the potential to be testable.

Preserving the second law

In a recent paper, Bianconi describes how the GfE theory can be applied to a Friedmann–Robertson–Walker (FRW) metric universe. The FRW model is one from general relativity that provides a first approximation to the universe’s behaviour, displaying simple characteristics such as isotropy (it looks the same in all directions when observed from a single point), homogeneity (globally uniform in distribution of its contents) and expansion (a property observed in the universe).

The expansion is driven by the dominant composition of the universe, such as dark matter, matter, or radiation. As the universe expands, its volume also increases, along with its total entropy. Due to this growth, the local entropy per unit volume decreases over time, as there is the same amount of entropy contained in a now larger unit volume; the entropy density decreases (along with similar decaying behaviour for the local energy density). This decrease in local entropy in a universe of entropy growth provides a mechanism for low-entropy structures such as galaxies and even life forms to be created in an expanding universe.

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The question then remains: does this mechanism violate the second law of thermodynamics? Thankfully, Bianconi also answered this question for a non-empty universe described by the FRW metric. To find the total entropy of such a universe, the entropy density must be integrated over a space–time region, which, due to the fact that the volume increases, is a time-dependent quantity. This is a result of the expansion being faster than the decay of the entropy density. For radiation- and matter-dominated universes, then, the entropy is increasing in time, specifically following the second law of thermodynamics even when the entropy density is decreasing locally. To summarize, while entropy density decreases locally, the total entropy of the universe is still increasing in this model.

Bianconi emphasizes that the GfE theory is still in its infancy, and experimental verifications are required. However, this work highlights the intrinsically thermodynamic nature of the GfE theory, which opens new avenues for both classical and quantum gravity. By framing gravity in terms of quantum information and entropy, the theory may offer an alternative route towards quantizing gravity—one of the longstanding challenges in fundamental physics.

Bianconi describes her research in Physical Review D.

The post Could quantum information theory explain universe evolution? appeared first on Physics World.

Top-cited authors from India and North America share their tips for early-career researchers

Michael Banks — Tue, 03 Feb 2026 13:24:16 +0000

Some 20 papers from researchers based in North America have been recognized with a Top Cited Paper award for 2025 from IOP Publishing, which publishes Physics World.

The prize is given to corresponding authors who have papers published in both IOP Publishing and its partners’ journals from 2022 to 2024 that are in the top 1% of the most cited papers.

Meanwhile, 29 papers from India have been recognized with a Top Cited Paper award for 2025.

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Below, some of the winners of the 2025 top-cited paper award from India and North America outline their tips for early-career researchers who are looking to boost the impact of their work.

Answers have been edited for clarity and brevity.

Shikhar Mittal from Tata Institute of Fundamental Research in Mumbai: Early-career researchers, especially PhD students, often underestimate the importance of presentation and visibility when it comes to their work. While doing high-quality research is, of course, essential, it is equally important to write your paper clearly and professionally. Even the tiniest of details, such as consistent scientific notation, clean figures, correct punctuation and avoiding typos can make a big difference. A paper full of careless errors may not be taken seriously, even if it contains strong scientific results.

Another crucial aspect is visibility. It is important to actively advertise your research by presenting your work at conferences and reaching out to researchers who are working on related topics. If someone misses citing your relevant work, a polite message can often lead to recognition and even collaboration. Being proactive in how you communicate and share your research can significantly improve its impact.

Sandip Mondal from the Indian Institute of Technology Bombay: Don’t try to solve everything at once. Pick a focused, well-motivated question and go deep into it. It’s tempting to jump on “hot topics”, but the work that lasts – and gets cited – is methodologically sound, reproducible and well-characterized. Even incremental advances, if rigorously done, can be very impactful.

Another tip is to work with people who bring complementary skills — whether in theory, device fabrication or characterization. Collaboration isn’t just about co-authors; it’s about deepening the quality of your work. And once your paper is published, your job isn’t done. Promote it as visibility breeds engagement, which leads to impact.

Sarika Jalan from the Indian Institute of Technology Indore: Try to go in-depth into the problem you are working on. Publications alone cannot give visibility, its understanding and creativity that will matter in the long run.

Marcia Rieke from the University of Arizona: Write clearly and concisely. I would also suggest being careful with your choice of journal – high-impact-factor journals can be great but may lead to protracted refereeing while other journals are very reputable and sometimes have faster publication rates.

Dan Scolnic from Duke University: At some point there needs to be a transition from thinking about “number of papers” to “number of citations” instead. Graduate students typically talk about writing as many papers as possible – that’s the metric. But at some point scientists start getting judged on the impact of their papers, which is most easily understood with citations. I’m not saying one should e-mail anyone with a paper to cite them, but rather, to think about what one wants to put time in to work on. One should say “I’d like to work on this because I think it can have a big impact”.

P Veeresha from CHRIST University in Bangalore: Build a strong foundation in the fundamentals and always think critically about what society truly needs. Also focus on how your research can be different, novel, and practically useful. It’s important to present your work in a simple and clear way so that it connects with both the academic community and real-world applications.

Parasuraman Swaminathan from the Indian Institute of Technology Madras: Thorough research is critical for good quality research, be bold and try to push the boundaries of your chosen topic.

Arnab Pal from the Institute of Mathematical Sciences in Chennai: Focus on asking meaningful, well-motivated questions rather than just solving technically difficult problems. Write clearly and communicate your ideas with simplicity and purpose. Engage with the research community early through talks, preprints and collaborations. Above all, be patient and consistent; impactful work often takes time to be recognized.

Steven Finkelstein from the University of Texas at Austin: Work on topics that both you think are interesting, and that others find interesting, and above all work with people who you trust.

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+ + + https://physicsworld.com/?p=130190 + Kiefer Vermeulen is research team lead at Delft Circuits in the Netherlands

The post Ask me anything: Kiefer Vermeulen – ‘We had to figure everything out on a shoestring budget and on a really challenging timescale’ appeared first on Physics World.

A hybrid energy system for heating, cooling and generating electricity

Isabelle Dumé — Mon, 14 Sep 2026 09:00:46 +0000

Researchers at the Karlsruhe Institute of Technology (KIT) in Germany and Stanford University in the US have developed an energy-collecting device that can simultaneously cool, produce electricity and generate heat. In their prototype, a radiative cooling layer reached 6.5 °C below ambient temperature while a solar collector generated electricity and reached nearly 111 °C.

“The new system could be installed on the roofs and facades of buildings to provide these three energy services at once,” says Gan Huang, who is head of the Hybrid Solar Technologies lab at KIT. “It could also be attractive for AI data centres that need both intensive power and cooling at the same time.”

As many of us have experienced, summer in the northern hemisphere has been particularly hot this year – a situation that is only likely to worsen in the future as the effects of climate change take hold. With this warming will come the increased need for air conditioning to cool down buildings. The problem is that current compression-based systems consume a lot of electricity and produce large amounts of CO₂.

Passive daytime radiative cooling

A potential alternative is passive daytime radiative cooling (PDRC), in which heat is continuously exchanged between objects at different temperatures by absorbing and emitting thermal radiation. When the heat absorbed by the material is less than the energy radiated to outer space, it can cool down during the day – even without electricity.

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Our planet naturally experiences this effect by radiating heat out to space. This allows it to cool down at night because its temperature (of around 300 K) is much higher than that of outer space (around 3 K) and there is no incident solar irradiation from the Sun at night.

A good PDRC material needs to satisfy several criteria. For one, it must reflect sunlight strongly at solar spectrum wavelengths (of 0.3 to 2.5 µm) to avoid it heating up. It also needs to emit heat strongly in the long-wave infrared (LWIR) wavelengths (of 8–13 µm) where the atmosphere is more transparent to infrared radiation, so that it can lose energy to the cold sky. Over the past decade, researchers have succeeded in developing a wide range of PDRC materials, including multilayer nanophotonic emitters, single-layer polymers on reflectors and porous ceramics. However, conventional PDRC systems cannot harvest the coldness of outer space and solar energy from the same surface at the same time.

A hybrid PDRC and photovoltaic-thermal collector

In the new work, which is detailed in Cell Reports Physical Science, the KIT researchers made a hybrid PDRC and photovoltaic-thermal collector. The emitting layer in the device, which is transparent, consists of a silica substrate coated with the silicone polymer polydimethylsiloxane. This layer allows sunlight to pass through while simultaneously emitting heat as LWIR radiation through the atmospheric window. Beneath the transparent emitter, a Fresnel lens concentrates the transmitted sunlight onto the (gallium arsenide-based) photovoltaic-thermal collector mounted on a two-axis solar tracker. This is where electricity is generated.

In outdoor experiments performed during the day, the prototype simultaneously achieved cooling of up to 6.5 °C below ambient temperature, an electrical power density of 60.6 W/m² and heating up to 110.8 °C. “This is exciting,” says Huang, “because it shows that the hot Sun and the cold universe can be harvested together, rather than treated as separate resources as has been the case until now.”

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The main challenge was ensuring that the solar collector became hot while the radiative cooler stayed cool, he explains. “We achieved this by concentrating the transmitted sunlight onto a much smaller solar collector underneath the transparent cooling layer, so reducing thermal interference between the hot and cold parts in the device.”

The team is now busy improving the efficiency and practical design of its system. “We are already working on a better optical design, improved thermal management and more efficient solar cells,” reveals Huang.

“The Sun is not the only renewable energy resource in the sky, the coldness of outer space is another,” he says. “We believe there are many exciting possibilities for a new generation of energy systems if we learn how to manage both these together.”

The post A hybrid energy system for heating, cooling and generating electricity appeared first on Physics World.

Twenty-three nominations, yet no Nobel prize: how Chien-Shiung Wu missed out on the top award in physics

No Author — Tue, 03 Feb 2026 11:00:08 +0000

The facts seem simple enough. In 1957 Chen Ning Yang and Tsung-Dao Lee won the Nobel Prize for Physics “for their penetrating investigation of the so-called parity laws which has led to important discoveries regarding the elementary particles”. The idea that parity is violated shocked physicists, who had previously assumed that every process in nature remains the same if you reverse all three spatial co-ordinates.

Thanks to the work of Lee and Yang, who were Chinese-American theoretical physicists, it now appeared that this fundamental physics concept wasn’t true (see box below). As Yang once told Physics World columnist and historian of science Robert Crease, the discovery of parity violation was like having the lights switched off and being so confused that you weren’t sure you’d be in the same room when they came back on.

But one controversy has always surrounded the prize.

Lee and Yang published their findings in a paper in October 1956 (Phys. Rev. 1 254), meaning that their Nobel prize was one of the rare occasions that satisfied Alfred Nobel’s will, which says the award should go to work done “during the preceding year”. However, the first verification of parity violation was published in February 1957 (Phys. Rev. 105 1413) by a team of experimental physicists led by Chien-Shiung Wu at Columbia University, where Lee was also based. (Yang was at the Institute for Advanced Study in Princeton at the time.)

Surely Wu, an eminent experimentalist (see box below “Chien-Shiung Wu: a brief history”), deserved a share of the prize for contributing to such an fundamental discovery? In her paper, entitled “Experimental Test of Parity Conservation in Beta Decay”, Wu says she had “inspiring discussions” with Lee and Yang. Was gender bias at play, did her paper miss the deadline, or was she simply never nominated?

The Wu experiment

(Courtesy: IOP Publishing)

Parity is a property of elementary particles that says how they behave when reflected in a mirror. If the parity of a particle does not change during reflection, parity is said to be conserved. In 1956 Tsung-Dao Lee and Chen Ning Yang realized that while parity conservation had been confirmed in electromagnetic and strong interactions, there was no compelling evidence that it should also hold in weak interactions, such as radioactive decay. In fact, Lee and Yang thought parity violation could explain the peculiar decay patterns of K mesons, which are governed by the weak interaction.

In 1957 Chien-Shiung Wu suggested an experiment to check this based on unstable cobalt-60 nuclei radioactively decaying into nickel-60 while emitting beta rays (electrons). Working at very low temperatures to ensure almost no random thermal motion – and thereby enabling a strong magnetic field to align the cobalt nuclei with their spins parallel – Wu found that far more electrons were emitted in a downward direction than upward.

In the figure, (a) shows how a mirror image of this experiment should also produce more electrons going down than up. But when the experiment was repeated, with the direction of the magnetic field reversed to change the direction of the spin as it would be in the mirror image, Wu and colleagues found that more electrons were produced going upwards (b). The fact that the real-life experiment with reversed spin direction behaved differently from the mirror image proved that parity is violated in the weak interaction of beta decay.

Back then, the Nobel statutes stipulated that all details about who had been nominated for a Nobel prize – and why the winners were chosen by the Nobel committee – were to be kept secret forever. Later, in 1974, the rules were changed, allowing the archives to be opened 50 years after an award had been made. So why did the mystery not become clear in 2007, half a century after the 1957 prize?

The reason is that there is a secondary criterion for prizes awarded by the Royal Swedish Academy of Sciences – in physics and chemistry – which is that the archive must stay shut for as long as a laureate is still alive. Lee and Yang were in their early 30s when they were awarded the prize and both went on to live very long lives. Lee died on 24 August 2024 aged 97 and it was not until the death of Yang on 18 October 2025 at 103 that the chance to solve the mystery finally arose.

Chien-Shiung Wu: a brief history

Overlooked for a Nobel Chien-Shiung Wu in 1963 at Columbia University by which time she had already received the first three of her 23 known nominations for a Nobel prize. (Courtesy: Smithsonian Institution)

Born on 31 May 1912 in Jiangsu province in eastern China, Chien-Shiung Wu graduated with a degree in physics from National Central University in Nanjing. After a few years of research in China, she moved to the US, gaining a PhD at the University of California at Berkeley in 1940. Three years later Wu took up a teaching job at Princeton University in New Jersey – a remarkable feat given that women were not then even allowed to study at Princeton.

During the Second World War, Wu joined the Manhattan atomic-bomb project, working on radiation detectors at Columbia University in New York. After the conflict was over, she started studying beta decay – one of the weak interactions associated with radioactive decay. Wu famously led a crucial experiment studying the beta decay of cobalt-60 nuclei, which confirmed a prediction made in October 1956 by her Columbia colleague Tsung-Dao Lee and Chen Ning Yang in Princeton that parity can be violated in the weak interaction.

Lee and Yang went on to win the 1957 Nobel Prize for Physics but the Nobel Committee was not aware that Lee had in fact consulted Wu in spring 1956 – several months before their paper came out – about potential experiments to prove their prediction. As she was to recall in 1973, studying the decay of cobalt-60 was “a golden opportunity” to test their ideas that she “could not let pass”.

The first woman in the Columbia physics department to get a tenured position and a professorship, Wu remained at Columbia for the rest of her career. Taking an active interest in physics well into retirement, she died on 16 February 1997 at the age of 84. Only now, with the publication of this Physics World article, has it become clear that despite receiving 23 nominations from 18 different physicists in 16 years between 1958 and 1974, she never won a Nobel prize.

Entering the archives

As two physicists based in Stockholm with a keen interest in the history of science, we had already examined the case of Lise Meitner, another female physicist who never won a Nobel prize – in her case for fission. We’d published our findings about Meitner in the December 2023 issue of Fysikaktuellt – the journal of the Swedish Physical Society. So after Yang died, we asked the Center for History of Science at the Royal Swedish Academy of Sciences if we could look at the 1957 archives.

A previous article in Physics World from 2012 by Magdolna Hargittai, who had spoken to Anders Bárány, former secretary of the Nobel Committee for Physics, seemed to suggest that Wu wasn’t awarded the 1957 prize because her Physical Review paper had been published in February of that year. This was after the January cut-off and therefore too late to be considered on that occasion (although the trio could have been awarded a joint prize in a subsequent year).

History in the making Left image: Mats Larsson (centre) and Ramon Wyss (left) at the Center for History of Science at the Royal Swedish Academy of Sciences in Stockholm, Sweden, on 13 November 2025, where they become the first people to view the archive containing information about the nominations for the 1957 Nobel Prize for Physics. They are shown here in the company of centre director Karl Grandin (right). Right image: Larsson and Wyss with their hands on the archives, on which this Physics World article is based. (Courtesy: Anne Miche de Malleray)

After receiving permission to access the archives, we went to the centre on Thursday 13 November 2025, where – with great excitement – we finally got our hands on the thick, black, hard-bound book containing information about the 1957 Nobel prizes in physics and chemistry. About 500 pages long, the book revealed that there were a total of 58 nominations for the 1957 Nobel Prize for Physics – but none at all for Wu that year. As we shall go on to explain, she did, however, receive a total of 23 nominations over the next 16 years.

Lee and Yang, we discovered, received just a single nomination for the 1957 prize, submitted by John Simpson, an experimental physicist at the University of Chicago in the US. His nomination reached the Nobel Committee on 29 January 1957, just before the deadline of 31 January. Simpson clearly had a lot of clout with the committee, which commissioned two reports from its members – both Swedish physicists – based on his recommendation. One was by Oskar Klein on the theoretical aspects of the prize and the other by Erik Hulthén on the experimental side of things.

Report revelations

Klein devotes about half of his four-page report to the Hungarian-born theorist Eugene Wigner, who – we discovered – received seven separate nominations for the 1957 prize. In his opening remarks, Klein notes that Wigner’s work on symmetry principles in physics, first published in 1927, had gained renewed relevance in light of recent experiments by Wu, Leon Lederman and others. According to Klein, these experiments cast a new light on the fundamental symmetry principles of physics.

Klein then discusses three important papers by Wigner and concludes that he, more than any other physicist, established the conceptual background on symmetry principles that enabled Lee and Yang to clarify the possibilities of experimentally testing parity non-conservation. Klein also analyses Lee and Yang’s award-winning Physical Review paper in some detail and briefly mentions subsequent articles of theirs as well as papers by two future Nobel laureates – Lev Landau and Abdus Salam.

Klein does not end his report with an explicit recommendation, but identifies Lee, Yang and Wigner as having made the most important contributions. It is noteworthy that every physicist mentioned in Klein’s report – apart from Wu – eventually went on to receive a Nobel Prize for Physics. Wigner did not have to wait long, winning the 1963 prize together with Maria Goeppert Mayer and Hans Jensen, who had also been nominated in 1957.

As for Hulthén’s experimental report, it acknowledges that Wu’s experiment started after early discussions with Lee and Yang. In fact, Lee had consulted Wu at Columbia on the subject of parity conservation in beta-decay before Lee and Yang’s famous paper was published. According to Wu, she mentioned to Lee that the best way would be to use a polarized cobalt-60 source for testing the assumption of parity violation in beta-decay.

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Many physicists were aware of Lee and Yang’s paper, which was certainly seen as highly speculative, whereas Wu realized the opportunity to test the far-reaching consequences of parity violation. Since she was not a specialist of low-temperature nuclear alignment, she contacted Ernest Ambler at the National Bureau of Standards in Washington DC, who was a co-author on her Physics Review paper of 15 February 1957.

Hulthén describes in detail the severe technical challenges that Wu’s team had to overcome to carry out the experiment. These included achieving an exceptionally low temperature of 0.001 K, placing the detector inside the cryostat, and mitigating perturbations from the crystalline field that weakened the magnetic field’s effectiveness.

Despite these difficulties, the experimentalists managed to obtain a first indication of parity violations, which they presented on 4 January 1957 at a regular lunch that took place at Columbia every Friday. The news of these preliminary results spread like wildfire throughout the physics community, prompting other groups to immediately follow suit.

Hulthén mentions, for example, a measurement of the magnetic moment of the mu (μ) meson (now known as the muon) that Richard Garvin, Leon Lederman and Marcel Weinrich performed at Columbia’s cyclotron almost as soon as Lederman had obtained information of Wu’s work. He also cites work at the University of Leiden in the Netherlands led by C J Gorter that apparently had started to look into parity violation independently of Wu’s experiment (Physica 23 259).

Wu’s nominations

It is clear from Hulthén’s report that the Nobel Physics Committee was well informed about the experimental work carried out in the wake of Lee and Yang’s paper of October 1956, in particular the groundbreaking results of Wu. However, it is not clear from a subsequent report dated 20 September 1957 (see box below) from the Nobel Committee why Wigner was not awarded a share of the 1957 prize, despite his seven nominations. Nor is there any suggestion of postponing the prize a year in order to include Wu. The report was discussed on 23 October 1957 by members of the “Physics Class” – a group of physicists in the academy who always consider the committee’s recommendations – who unanimously endorsed it.

The Nobel Committee report of 1957

(Courtesy: The Nobel Archive, The Royal Swedish Academy of Sciences, Stockholm)

This image is the final page of a report written on 20 September 1957 by the Nobel Committee for Physics about who should win the 1957 Nobel Prize for Physics. Dated 20 September 1957 and published here for the first time since it was written, the English translation is as follows. “Although much experimental and theoretical work remains to be done to fully clarify the necessary revision of the parity principle, it can already be said that a discovery with extremely significant consequences has emerged as a result of the above-mentioned study by Lee and Yang. In light of the above, the committee proposes that the 1957 Nobel Prize in Physics be awarded jointly to: Dr T D Lee, New York, and Dr C N Yang, Princeton, for their profound investigation of the so-called parity laws, which has led to the discovery of new properties of elementary particles.” The report was signed by Manne Siegbahn (chair), Gudmund Borelius, Erik Hulthén, Oskar Klein, Erik Rudberg and Ivar Waller.

Most noteworthy with regard to this meeting of the Physics Class was that Meitner – who had also been overlooked for the Nobel prize – took part in the discussions. Meitner, who was Austrian by birth, had been elected a foreign member of the Royal Swedish Academy of Sciences in 1945, becoming a “Swedish member” after taking Swedish citizenship in 1951. In the wake of these discussions, the academy decided on 31 October 1957 to award the 1957 Nobel Prize for Physics to Lee and Yang. We do not know, though, if Meitner argued for Wu to be awarded a share of that year’s prize.

A total of 23 nominations to give a Nobel prize to Wu reached the Nobel Committee on 10 separate years and she was nominated by 18 leading physicists, including various Nobel-prize winners and Tsung-Dao Lee himself
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Although Wu did not receive any nominations in 1957, she was nominated the following year by the 1955 Nobel laureates in physics, Willis Lamb and Polykarp Kusch. In fact, after Lee and Yang won the prize, nominations to give a Nobel prize to Wu reached the committee on 10 separate years out of the next 16 (see graphic below). She was nominated by a total of 18 leading physicists, including various Nobel-prize winners and Lee himself. In fact, Lee nominated Wu for a Nobel prize on three separate occasions – in 1964, 1971 and 1972.

However, it appears she was never nominated by Yang (at the time of writing, we only have archive information up to 1974). One reason for Lee’s support and Yang’s silence could be attributed to the early discussions that Lee had with Wu, influencing the famous Lee and Yang paper, which Yang may not have been aware of. It is also not clear why Lee and Yang never acknowledged their discussion with Wu about the cobalt-60 experiment that was proposed in their paper; further research may shed more light on this topic.

Following Wu’s nomination in 1958, the Nobel Committee simply re-examined the investigations already carried out by Klein and Hulthén. The same procedure was repeated in subsequent years, but no new investigations into Wu’s work were carried out until 1971 when she received six nominations – the highest number she got in any one year.

Nominations for Wu from 1958 to 1974

(Courtesy: IOP Publishing)

Our examination of the newly released Nobel archive from 1957 indicates that although Chien-Shiung Wu was not nominated for that year’s prize, which was won by Chen Ning Yang and Tsung-Dao Lee, she did receive a total of 23 nominations over the next 16 years (1974 being the last open archive at the time of writing). Those 23 nominations were made by 18 different physicists, with Lee nominating Wu three times and Herwig Schopper, Emilio Segrè and Ryoya Utiyama each doing so twice. The peak year for nominations for her was 1971 when she received six nominations. The archives also show that in October 1957 Werner Heisenberg submitted a nomination for Lee (but not Yang); it was registered as a nomination for 1958. The nomination is very short and it is not clear why Heisenberg did not nominate Yang.

That year the committee decided to ask Bengt Nagel, a theorist at KTH Royal Institute of Technology, to investigate the theoretical importance of Wu’s experiments. The nominations she received for the Nobel prize concerned three experiments. In addition to her 1957 paper on parity violation there was a 1949 article she’d written with her Columbia colleague R D Albert verifying Enrico Fermi’s theory of beta decay (Phys. Rev. 75 315) and another she wrote in 1963 with Y K Lee and L W Mo on the conserved vector current, which is a fundamental hypothesis of the Standard Model of particle physics (Phys. Rev. Lett. 10 253).

After pointing out that four of the 1971 nominations came from Wu’s colleagues at Columbia, which to us may have hinted at a kind of lobbying campaign for her, Nagel stated that the three experiments had “without doubt been of great importance for our understanding of the weak interaction”. However, he added, “the experiments, at least the last two, have been conducted to certain aspects as commissioned or direct suggestions of theoreticians”.

In Nagel’s view, Wu’s work therefore differed significantly from, for example, James Cronin and Val Fritsch’s famous discovery in 1964 of charge-parity (CP) violation in the decay of K^o mesons. They had made their discovery under their own steam, whereas (Nagel suggested) Wu’s work had been carried out only after being suggested by theorists. “I feel somewhat hesitant whether their theoretical importance is a sufficient motivation to render Wu the Nobel prize,” Nagel concluded.

Missed opportunity

The Nobel archives are currently not open beyond 1974 so we don’t know if Wu received any further nominations over the next 23 years until her her death in 1997. Of course, had Wu not carried out her experimental test of parity violation, it is perfectly possible that another physicist or group of physicists would have something similar in due course.

Nevertheless, to us it was a missed opportunity not to include Wu as the third prize winner alongside Lee and Yang. Sure, she could not have won the prize in 1957 as she was not nominated for it and her key publication did not appear before the January deadline. But it would simply have been a case of waiting a year and giving Wu and her theoretical colleagues the prize jointly in 1958.

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Multi-ion cancer therapy tackles the LET trilemma

Tami Freeman — Tue, 03 Feb 2026 09:00:45 +0000

Cancer treatments using heavy ions offer several key advantages over conventional proton therapy: a sharper Bragg peak and small lateral scattering for precision tumour targeting, as well as high linear energy transfer (LET). High-LET radiation induces complex DNA damage in cancer cells, enabling effective treatment of even hypoxic, radioresistant tumours. A team at the National Institutes for Quantum Science and Technology (QST) in Japan is now exploring the potential benefits of multi-ion therapy combining beams of carbon, oxygen and neon ions.

“Different ions exhibit distinct physical and biological characteristics,” explains QST researcher Takamitsu Masuda. “Combining them in a way that is tailored to the specific characteristics of a tumour and its environment allows us to enhance tumour control while reducing damage to surrounding healthy tissues.”

The researchers are using multi-ion therapy to increase the dose-averaged LET (LET_d) within the tumour, performing a phase I trial at the QST Hospital to evaluate the safety and feasibility of this LET_d escalation for head-and-neck cancers. But while high LET_d prescriptions can improve treatment efficacy, increasing LET_d can also deteriorate plan robustness. This so-called “LET trilemma” – a complex trade-off between target dose homogeneity, range robustness and high LET_d – is a major challenge in particle therapy optimization.

In their latest study, reported in Physics in Medicine & Biology, Masuda and colleagues evaluated the impact of range and setup uncertainties on LET_d-optimized multi-ion treatment plans, examining strategies that could potentially overcome this LET trilemma.

Robustness evaluation

The team retrospectively analysed the data of six patients who had previously been treated with carbon-ion therapy. Patients 1, 2 and 3 had small, medium and large central tumours, respectively, and adjacent dose-limiting organs-at-risk (OARs); and patients 4, 5 and 6 had small, medium and large peripheral tumours and no dose-limiting OARs.

Multi-ion therapy plans Reference dose and LET_d distributions for patients 1, 2 and 3 for multi-ion therapy with a target LET_d of 90 keV/µm. The GTV, clinical target volume (CTV) and OARs are shown in cyan, green and magenta, respectively. (Courtesy: Phys. Med. Biol.10.1088/1361-6560/ae387b)

For each case, the researchers first generated baseline carbon-ion therapy plans and then incorporated oxygen- or neon-ion beams and tuned the plans to achieve a target LET_dof 90 keV/µm to the gross tumour volume (GTV).

Particle therapy plans can be affected by both range uncertainties and setup variations. To assess the impact of these uncertainties, the researchers recalculated the multi-ion plans to incorporate range deviations of +2.5% (overshoot) and –2.5% (undershoot) and various setup uncertainties, evaluating their combined effects on dose and LET_d distributions.

They found that range uncertainty was the main contributor to degraded plan quality. In general, range overshoot increased dose to the target, while undershoot decreased dose. Range uncertainties had the largest effect on small tumours and central tumours: patient #1 exhibited a deviation of around ±6% from the reference, while patient #3 showed a dose deviation of just ±1%. Robust target coverage was maintained in all large or peripheral tumours, but deteriorated in patient 1, leading to an uncertainty band of roughly 11%.

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“Wide uncertainty bands indicate a higher risk that the intended dose may not be accurately delivered,” Masuda explains. “In particular, a pronounced lower band for the GTV suggests the potential for cold spots within the tumour, which could compromise local tumour control.”

The team also observed that range undershoot increased LET_d and overshoot decreased it, although absolute differences in LET_d within the entire target were small. Importantly, all OAR dose constraints were satisfied even in the largest error scenarios, with uncertainty bands comparable to those of conventional carbon-ion treatment plans.

Addressing the LET trilemma

To investigate strategies to improve plan robustness, the researchers created five new plans for patient 1, who had a small, central tumour that was particularly susceptible to uncertainties. They modified the original multi-ion plan (carbon- and oxygen-ion beams delivered at 70° and 290°) in five ways: expanding the target; altering the beam angles to orthogonal or opposing arrangements; increasing the number of irradiation fields to a four-field arrangement; and using oxygen ions for both beam ports (“heavier-ion selection”).

The heavier-ion selection plan proved the most effective in mitigating the effects of range uncertainty, substantially narrowing the dose uncertainty bands compared with the original plan. The team attribute this to the inherently higher LET_d in heavier ions, making the 90 keV/µm target easier to achieve with oxygen-ion beams alone. The other plan modifications led to limited improvements.

Improving robustness Dose–volume histograms for patient 1, for the original multi-ion plan and the heavier-ion selection plan, showing the combined effects of range and setup uncertainties. Solid, dashed and dotted curves represent the reference plans, and upper and lower uncertainty scenarios, respectively. (Courtesy: Phys. Med. Biol.10.1088/1361-6560/ae387b)

These findings suggest that strategically employing heavier ions to enhance plan robustness could help control the balance among range robustness, uniform dose and high LET_d – potentially offering a practical strategy to overcome the LET trilemma.

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“Clinically, this strategy is particularly well-suited for small, deep-seated tumours and complex, variable sites such as the nasal cavity, where range uncertainties are amplified by depth, steep dose gradients and daily anatomical changes,” says Masuda. “In such cases, the use of heavier ions enables robust dose delivery with high LET_d.”

The researchers are now exploring the integration of emerging technologies – such as robust optimization, arc therapy, dual-energy CT, in-beam PET and online adaptation – to minimize uncertainties. “This integration is highly desirable for applying multi-ion therapy to challenging cases such as pancreatic cancer, where uncertainties are inherently large, or hypofractionated treatments, where even a single error can have a significant impact,” Masuda tells Physics World.

The post Multi-ion cancer therapy tackles the LET trilemma appeared first on Physics World.

+ Mercury may not need an ancient dynamo to explain its magnetic crust + https://physicsworld.com/a/mercury-may-not-need-an-ancient-dynamo-to-explain-its-magnetic-crust/ + Fri, 11 Sep 2026 14:45:23 +0000 + + + + https://physicsworld.com/?p=130322 + New analyses of MESSENGER data find that present-day magnetic field can explain most of its crustal magnetism

The post Mercury may not need an ancient dynamo to explain its magnetic crust appeared first on Physics World.

New project takes aim at theory-experiment gap in materials data

Margaret Harris — Mon, 02 Feb 2026 13:00:36 +0000

Breaking action–reaction symmetry Non-reciprocal interactions occur when one particle influences another more strongly than it is influenced in return. This figure shows how unequal electrohydrodynamic attraction between differently sized particles generates non-reciprocal interactions and self-propelled particle pairs. (Courtesy: Yutaka Sumino, Tokyo University of Science, Japan)

Attractive interactions between particles do not necessarily lead to these particles aggregating. This is the new finding from researchers at the Tokyo University of Science in Japan who say this behaviour comes from non-reciprocal interactions amongst particles of different sizes that exert unequal forces on each other. These interactions could serve as a general design principle for creating active matter with a structure that continuously reorganizes rather than simply relaxing towards a static state.

Nature abounds with examples of active matter, with some well-known examples being flocks of birds, fish and insects, sheets of biological cells and swarms of bacteria. Researchers have been trying to copy this collective behaviour and make synthetic active materials – such as self-propelled colloids and dense phases of mechanically driven biopolymers – in the laboratory. Before such applications see the light of day, however, they need to first understand the fundamental physics of these systems.

In their new study, a team led by Yutaka Sumino and Kiwamu Yoshii of Tokyo University of Science’s department of applied physics, came across a system in which colloidal particles interact through electrohydrodynamic flow. “We found that mixing particles of two different sizes in such a system completely changed the collective behaviour of these particles,” explains Sumino. “Instead of forming increasingly large crystal-like aggregates, as is the case for particles with the same size, the system remained highly dynamic.”

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The physicists’ experiment involved suspending polystyrene colloidal particles with radii of 1 and 1.5 µm in water and confining them between transparent indium tin oxide-coated electrodes. This set up allowed them track more than 10,000 particles and quantitatively analyse their dynamics for more than an hour, as opposed to just a few minutes in previous such studies.

Newton’s third law holds

When the researchers applied an alternating electric field to the system, they observed electrohydrodynamic flows around the particles, the strength of which increased strongly as the size of the particles became bigger. The electrohydrodynamic-mediated attractive interactions therefore became asymmetric, they explain, something that causes larger particles to attract smaller ones more strongly. This imbalance leads to non-reciprocal interactions, meaning that a larger particle pushes a smaller one, but a smaller one doesn’t push back.

While the effective interaction between the particles appears to break Newton’s third law, it doesn’t because there is no violation of momentum conservation, explains Sumino: momentum is transferred to the surrounding fluid through the induced flows and is ultimately dissipated through friction with the substrate.

The researchers also observed that particles of different sizes spontaneously pair together to form asymmetric structures with a distinct front and tail. These pairs behave as self-propelled units and move through the suspension – even though individual particles cannot propel themselves. As more self-propelled pairs form, they assemble into larger clusters, but these clusters do not continue growing into large aggregates and instead repeatedly fragment, rearrange themselves and reform. Importantly, they note: “the larger particle tends to be at the front of these moving pairs. This head-heavy size asymmetry, together with excluded-volume interactions, promotes the fragmentation of larger clusters and thereby prevents continuous coarsening”.

Sumino and Yoshii combined their experiments with numerical simulations, thereby identifying non-reciprocal pair motion as the microscopic origin of this behaviour.

The results, they say, suggest that non-reciprocal interactions can serve as a general design principle for creating active materials with structures that continuously reorganize rather than simply relaxing toward a static state. “An interesting aspect,” explains Sumino, “is that self-propulsion does not need to be built into each individual particle: it can emerge collectively from non-reciprocal interactions between particles that do not self-propel on their own.”

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If such interactions can be controlled externally, they could provide a way to design microscopic systems that collectively gather, transport, fragment or mix materials, he tells Physics World. “Possible directions include programmable active materials and microrobotic systems, although these applications are still some way off.”

Reporting their findings in Physical Review Letters, the researchers say they would now like to understand how general this non-reciprocal mechanism is and whether the same principle – collective activity emerging from non-reciprocal interactions – can be transferred to other experimental systems. In the system studied in this work, the strength of the non-reciprocity depends on parameters such as particle size, composition and the applied electric field. By systematically tuning these parameters, they aim to explore what other types of collective states can be generated and whether transitions between them can be controlled.

“A more detailed hydrodynamic analysis of the system is also needed to develop a quantitative understanding of the interactions and ultimately predict the collective motion of the colloids,” says Sumino.

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The pros and cons of patenting

Honor Powrie — Mon, 02 Feb 2026 11:00:42 +0000

Could radioactive atoms in a Bose–Einstein condensate (BEC) form a “superradiant neutrino laser”? According to a paper published last year by Benjamin Jones of the University of Manchester and Joseph Formaggio of the Massachusetts Institute of Technology the answer is “yes”. We were intrigued by this proposal and commissioned the freelance physics writer Tim Wogan to write an article for us.

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As part of his reporting, Wogan sought the opinion of a BEC expert – James Thompson of NIST, JILA and the University of Colorado in Boulder. Thompson told us that he was sceptical of the viability of such a device – in particular, he pointed out that the de Broglie wavelength of the emitted neutrinos is much too short for superradiance to occur.

Now, another physicist (Wolfgang Ketterle, who shared a Nobel prize for his pioneering work on BECs) has published two papers that cast doubt on Jones and Formaggio’s proposal. All three papers are published in a very prestigious journal, so this is a scientific debate of note.

So what is superradiance, and how could it be used to create a source of coherent neutrinos?

Coherent burst

Superradiance was originally envisioned in an ensemble of excited atoms, each of which can decay by emitting a photon. Normally, the rate at which photons are emitted from such an ensemble is simply proportional to the number of atoms present. Double the number of atoms, and the rate of emission will double. However, if the ensemble is dense enough that the wavelength of the emitted photons is much longer than the separation between neighbouring atoms, the emission of a single photon will involve all of the atoms. What is more, the superradiant emission rate is proportional to square of the number of atoms. The result is short, intense burst of coherent radiation. It is this coherence that has caused some to refer to superradiant lasers – although the physics of lasers is different.

Jones and Formaggio’s proposal involves radioactive atoms that decay with the emission of a neutrino, rather than a photon. Their idea is to cool an ensemble of these atoms to near absolute zero so that it forms a BEC. This is a unique form of matter that can be described as a macroscopic quantum state. Under this condition, the duo argued that neutrinos would be emitted rapidly from a superradiant state.

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Now, Ketterle, Yu-Kun Lu and Hanzhen Lin at the Massachusetts Institute of Technology argue in two papers that such a superradiant neutrino laser is an impossibility. As well as backing up Thompson’s concerns about the short wavelength of the neutrinos, they point out that the atoms produced by the neutrino decays are fermions, and this precludes superradiance. They also showed that the recoil of atoms after neutrino emission would not allow the coherent emission of neutrinos to occur.

I think this is a fascinating subject and I hope that Jones and Formaggio can revive their proposal, because a BEC-based neutrino laser would be very cool!

You can read more about the debate in an article in Physics by Thompson and colleagues.

The post Doubts cast on ‘superradiant neutrino laser’ proposal appeared first on Physics World.

Porous material offers the benefits of graphene in 3D

Hamish Johnston — Thu, 10 Sep 2026 13:43:01 +0000

For any company or business, it’s important to recognize and protect intellectual property (IP). In the case of novel inventions, which can include machines, processes and even medicines, a patent offers IP protection and lets firms control how those inventions are used. Patents, which in most countries can be granted for up to 20 years, give the owner exclusive rights so that others can’t directly copy the creation. A patent essentially prevents others from making, using or selling your invention.

But there are more reasons for holding a patent than IP protection alone. In particular, patents go some way to protecting the investment that may have been necessary to generate the IP in the first place, such as the cost of R&D facilities, materials, labour and expertise. Those factors need to be considered when you’re deciding if patenting is the right approach or not.

Patents are tangible assets that can be sold to other businesses or licensed for royalties to provide your compay with regular income
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Patents are in effect a form of currency. Counting as tangible assets that add to the overall value of a company, they can be sold to other businesses or licensed for royalties to provide regular income. Some companies, in fact, build up or acquire significant patent portfolios, which can be used for bargaining with competitors, potentially leading to cross-licensing agreements where both parties agree to use each other’s technology.

Patents also say something about the competitive edge of a company, by demonstrating technical expertise and market position through the control of a specific technology. Essentially, patents give credibility to a company’s claims of its technical know-how: a patent shows investors that a firm has a unique, protected asset, making the business more appealing and attractive to further investment.

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However, it’s not all one-way traffic and there are obligations on the part of the patentee. Firstly, a patent holder has to reveal to the world exactly how their invention works. Governments favour this kind of public disclosure as it encourages broader participation in innovation. The downside is that whilst your competitors cannot directly copy you, they can enhance and improve upon your invention, provided those changes aren’t covered by the original patent.

It’s also worth bearing in mind that a patent holder is responsible for patent enforcement and any ensuing litigation; a patent office will not do this for you. So you’ll have to monitor what your competitors are up to and decide on what course of action to take if you suspect your patent’s been infringed. Trouble is, it can sometimes be hard to prove or disprove an infringement – and getting the lawyers in can be expensive, even if you win.

Money talks

Probably the biggest consideration of all is the cost and time involved in making a patent application. Filing a patent requires a rigorous understanding of “prior art” – the existing body of relevant knowledge on which novelty is judged. You’ll therefore need to do a lot of work finding out about relevant established patents, any published research and journal articles, along with products or processes publicly disclosed before the patent’s filing date.

Before it can be filed with a patent office, a patent needs to be written as a legal description, which includes all the legwork like an abstract, background, detailed specifications, drawings and claims of the invention. Once filed, an expert in the relevant technical field will be assigned to assess the worth of the claim; this examiner must be satisfied that the application is both unique and “non-obvious” before it’s granted.

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Even when the invention is judged to be technically novel, in order to be non-obvious, it must also involve an “inventive step” that would not be obvious to a person with “ordinary skill” in that technical field at the time of filing. The assessment phase can result in significant to-ing and fro-ing between the examiner and the applicant to determine exactly what is patentable. If insufficient evidence is found, the patent application will be refused.

Patents are only ever granted in a particular country or region, such as Europe, and the application process has to be repeated for each new place (although the information required is usually pretty similar). Translations may be required for some countries, there are fees for each application and, even if a patent is granted, you have to pay an additional annual bill to maintain the patent (which in the UK rises year on year).

Patents can take years to process, which is why many companies pay specialized firms to support their applications
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Patent applications, in other words, can be expensive and can take years to process. That’s why many companies pay specialized firms to support their patent applications. Those firms employ patent attorneys – legal experts with a technical background who help inventors and companies manage their IP rights by drafting patent applications, navigating patent office procedures and advising on IP strategy. Attorneys can also represent their clients in disputes or licensing deals, thereby acting as a crucial bridge between science/engineering and law.

Perspiration and aspiration

It’s impossible to write about patents without mentioning the impact that Thomas Edison had as an inventor. During the 20th century, he became the world’s most prolific inventor with a staggering 1093 US patents granted in his lifetime. This monumental achievement remained unsurpassed until 2003, when it was overtaken by the Japanese inventor Shunpei Yamazaki and, more recently, by the Australian “patent titan” Kia Silverbrook in 2008.

Edison clearly saw there was a lot of value in patents, but how did he achieve so much? His approach was grounded in systematic problem solving, which he accomplished through his Menlo Park lab in New Jersey. Dedicated to technological development and invention, it was effectively the world’s first corporate R&D lab. And whilst Edison’s name appeared on all the patents, they were often primarily the work of his staff; he was effectively being credited for inventions made by his employees.

I have a love–hate relationship with patents or at least the process of obtaining them
+ My guest in this episode of the Physics World Weekly podcast is Marco Caffio, who is co-founder of iGii. The UK-based company has developed a porous 3D carbon nanomaterial called Gii, which it manufactures for a range of customers and applications.
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Caffio describes Gii as a 3D version of graphene that delivers many of the useful electronic, structural and chemical properties of that 2D wonder material. Unlike graphene, which can be difficult to manufacture and integrate into devices, Caffio explains that Gii can be customized for use in practical technologies such as chemical sensors, batteries and heaters.
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We also chat about the genesis of the company and Caffio offers career advice to physicists who are keen on working in the materials-technology sector.
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The post Porous material offers the benefits of graphene in 3D appeared first on Physics World.
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How far ahead can we predict the weather?

Isabelle Dumé — Thu, 10 Sep 2026 12:00:54 +0000

What will the weather be like tomorrow, or next week or, indeed, in a month’s time? Today’s numerical weather predictions can easily answer the first two parts of this question, but they fall short beyond about 14 days. New work on predictability limits by scientists at the University of Miami and the NOAA Cooperative Institute for Marine and Atmospheric Studies (CIMAS) say that this maximum could be extended to around 129 days – but probably no further. Whether this limit can be reached in practice, however, will depend on future improvements in forecasting technologies, they say.

Numerical weather prediction was developed in the late 1940s. Indeed, it was one of the first major applications of electronic computers. As these have advanced, so have the predictions. Indeed, thanks to ever more sophisticated mathematical models capable of analysing increasing amounts of observational data, we can now predict, for example, when hurricanes will occur as far as eight days in advance – something that was deemed impossible even a few decades ago. But how far ahead can such predictions be made?

Previous attempts to determine this predictability limit have largely relied on analysing the behaviour of very small perturbations in the atmosphere. These tiny errors, however, are inaccessible either observationally or via numerical modelling, explains Zoltan Toth of the NOAA who led this new study together with his colleague Wei Zhang. “These past studies therefore had to make some assumptions about the behaviour of the small errors, and these assumptions are necessarily somewhat arbitrary.”

Analysing the energetic balance of the atmosphere

The method developed by Toth, Zhang and their colleagues makes no reference to this error behaviour and instead goes back to analysing the energetic balance of the atmosphere, which continually absorbs solar radiation on the molecular level. In their approach, the researchers began by considering how our planet’s atmosphere would behave as a closed system, the deterministic dynamics of which preserves information about its initial state, assumed to be perfectly known. In theory, such a hypothesis would allow forecasts of the atmosphere’s behaviour right out to infinity. This is not possible in reality, they explain, because the atmosphere is obviously not a closed system: it receives and emits radiation. In the real atmosphere, the phases of photons in sunlight are completely random and cannot be determined, injecting quantum-scale uncertainty into the atmosphere.

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These unknown quantum characteristics act as noise and destroy any retained information, beginning first of all on the smallest scales, explain the researchers. As these scales become bigger, noise eventually affects all parts of the system. When the total energy in the atmosphere is entirely replaced, the ability to make any prediction is completely lost.

“Using the relatively well-measured quantities of total energy in the atmosphere and the incoming and outgoing solar radiation fluxes at its upper boundary, we estimate that the range of skilful forecasts could potentially be extended from 14 days as at present to 129 (±7) days at the most,” explains Toth.

Very different from the mainstream discourse

“This result is very different from the mainstream discourse about atmospheric predictability, which to this day is strongly influenced by early publications in the field,” adds Toth. “More recently even, the authors of a 2018 article in the Bulletin of the American Meteorological Society speculated on whether current forecast systems are reaching their limits for when it comes to predicting tropical cyclones. In 2020, we argued that this limit is at least decades, if not much farther away.”

The theoretical foundation for the new methodology to determine the time limit of predictability is rather simple, he says. “At its core is a conceptual realization, which came to us intuitively. This is that the energy turnover time (that is, the time it takes for all energy in the atmosphere to be replaced by incoming solar radiation) is equivalent to the upper limit of predictability.”

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While there is no complex mathematics involved, Toth notes that he and his colleagues had to find a way to describe the technique in a readily understandable way – something that was not easy, he admits, given the complexity of the subject.

Looking ahead, the researchers, who detail their present work in Advances in Atmospheric Sciences, are now looking into several other independent ways to estimate the limit of predictability. “There is no doubt, this limit has a theoretical feel to it,” Toth tells Physics World. “Yet there are a number of very practical implications for both traditional equation- and AI-based modelling of the atmosphere following on from the theory of predictability that we are also exploring in a series of ongoing studies.”

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Skyrmion topology makes long-distance optical communications more robust

Isabelle Dumé — Thu, 10 Sep 2026 07:11:10 +0000

Researchers at the University of the Witwatersrand (Wits) in Johannesburg, South Africa, have succeeded in harnessing a relatively unexplored property of light – its topology – to robustly transfer information through the atmosphere. The work could advance the development of more reliable long-distance optical communications, including space-based ones, and connect remote and underserved communities worldwide.

Their work is detailed in two separate studies, one based on classical and the other on quantum optics. These studies show that the topological information can remain remarkably robust – even when the states of light carrying this information are subject to the severe distortions caused by atmospheric turbulence. Instead of relying entirely on increasingly sophisticated hardware or computational algorithms to correct atmospheric distortions before or after light transmission, the new concept provides a fundamentally different way of thinking about robust optical communication in complex environments, such as air or water, they say.

Both studies are based on the same fundamental idea: creating an optical topological structure known as a skyrmion in a light field and testing whether it remains robust when it passes through a distorting environment, explains Andrew Forbes, who is head of the Structured Light Lab at the Wits School of Physics. Skyrmions are quasiparticles with a two-dimensional, knot-like structure and were first observed in magnetic materials. They have, however, recently been seen in electromagnetic fields and the electric field of light waves. Here, the swirling structures are created by twisting the polarization or spin vectors of light in space so that every polarization is found exactly once, twice, three times and so on – the count being the skyrmion number. Skyrmions are topologically stable, which means that external perturbations do not affect them in any way.

Real-world test

In the first study, Forbes and colleagues used laser light with a wavelength of 532 nm shaped into various vectorial beams using a spatial light modulator and a modified Mach–Zehnder interferometer to generate optical skyrmions with skyrmion numbers of 1, 2 and 3. These numbers, which are always whole integers, describe how twisted the vortex-like structure of the skyrmion is. They then sent the laser light through a 270-m-long real-world free-space optical link located on Wits’ Braamfontein campus in the centre of Johannesburg.

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The researchers measured the topology of the skyrmions with a Stokes polarimetry setup and found that the skyrmion number remains robust in a wide variety of atmospheric conditions, ranging from “calm, cool morning air to the highly erratic and intense distortions at midday” when it is hotter. “This result holds true even when the vectorial polarization of the underlying laser beam has been highly scrambled by atmospheric turbulence effects – and was therefore unrecognizable,” says Forbes.

In-built correlations

In the second work, the team created the topology through the in-built correlations between two photons entangled in their optical angular momentum (OAM). The OAM quantum states are not themselves stable in distorting environments and the information they encode is easily lost. The researchers investigated the robustness of a skyrmion with a skyrmion number of 1 in a controlled laboratory environment by studying photons in media with varying levels of turbulence.

The result? Despite local distortions, the skyrmions maintained topological numbers close to 1. This, they say, suggests the topological number is fundamentally decoupled from modal crosstalk induced by the turbulence and the spreading of an individual photon’s OAM.

Despite the very different physical systems, both experiments reveal a similar result, says Forbes: the conventional properties of optical fields can be strongly degraded by distortions, while the topological information encoded in those states remains remarkably robust. Together, the two works demonstrate that topology can be harnessed in both classical and quantum optical systems as a robust carrier of information in very different communication and information-processing scenarios.

Robust protection

Topology is a concept that appears throughout physics, from fundamental particle physics to magnetism and condensed matter systems. In many of these systems, explains Forbes, topology comes with a physical protection mechanism – such as an energy barrier – that explains why a topological structure is resistant to external disturbances. In optics, however, the situation is rather different. Optical topologies can be created and manipulated with relative ease, but their robustness is not necessarily guaranteed by any particular underlying physical protection mechanism. “We therefore wanted to address a fundamental question: how robust is optical topology when light encounters a real-world, highly distorting environment?

“The atmosphere provides a particularly interesting testbed because it is highly relevant to optical sensing and communications and represents an extreme case where the distortions vary rapidly both in space and time,” he tells Physics World. “Demonstrating robustness in this setting was therefore both a fundamental test of the dynamics and resilience of optical topologies and an indication of its potential practical value.”

Hurdles and challenges

One of the major challenges was simply doing precision optical experiments outdoors, he adds. “We had to contend with the unpredictability of nature: changes in sunlight and temperature, wind, rain and even the thermal expansion of buildings, which can affect optical alignment, making it difficult to maintain stable measurements over long periods.”

Another hurdle to overcome was to find a way of measuring the optical topology itself. Existing methods to do this can be quite sensitive to experimental noise and imperfections, so the researchers say they had to carefully distinguish genuine changes in the optical channel from apparent changes introduced by the measurement process. Ultimately, this meant developing new ways to both obtain and process the experimental data so that they could reliably track the topological properties of the light despite the noise that was present.

Applications include free-space optical, satellite and space communications, and linking remote or underserved communities, where atmospheric turbulence and the lack of physical infrastructure can present significant challenges, says Forbes. “More broadly, topology could be useful beyond communication,” he adds. “Indeed, its underlying robustness could potentially be exploited for optical sensing, information processing and other applications where light has to propagate through complex or noisy environments.”

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The quantum experiment adds another possibility, he notes. “We know that entanglement decays in real-world conditions that are not pristine. Our work shows that despite this, the quantum information stored in the topology remains intact. This may allow us to distribute information across a quantum network in a more reliable and robust manner.”

Looking ahead, the Wits researchers say they will now assess whether the robustness they have observed extends to other kinds of challenging environments, such as underwater and biological tissue, where scattering, birefringence and other phenomena can be much more prevalent than in the atmosphere.

“We also want to develop detectors and techniques for measuring optical topology,” says Forbes. “Improving how we characterize these structures will be important for moving from proof-of-principle experiments towards practical applications.

“Finally, we would like to actually exploit the robustness of the topology we have identified in high-speed communication experiments. This means implementing realistic communication protocols and investigating how much information can be reliably transmitted using a ‘topological alphabet’.”

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Bilayer approach ramps performance of all-perovskite triple-junction solar cells

Bashi Thipe — Wed, 09 Sep 2026 14:00:50 +0000

Researchers at the Helmholtz-Zentrum Berlin (HZB) in Germany have overcome a long-standing barrier in next-generation photovoltaics by developing a new type of all-perovskite triple-junction solar cell. Perovskites are a class of synthetic materials with a unique crystal structure that excel at absorbing light, while a triple-junction design stacks three distinct perovskite sub-cells together, each tuned to capture a different part of the solar spectrum to maximize energy harvesting. With this combination, the device achieved a power conversion efficiency of 27.3%.

Stacking three such individual sub-cells allows multi-junction devices to bypass the theoretical efficiency ceiling of traditional single-junction solar cells. However, their real-world implementation has been severely constrained by optical and electrical losses at the buried interfaces of their narrow-band-gap sub-cells. By introducing a novel graphene oxide and self-assembled monolayer (SAM) bilayer strategy, the HZB team has effectively suppressed these losses, unlocking both high efficiency and unprecedented operational stability.

The challenge of buried interfaces

The main bottleneck in multi-junction all-perovskite architectures centres on the narrow-band-gap tin-lead bottom sub-cell, which captures near-infrared light. For years, the field has relied on an organic polymer called PEDOT:PSS as the hole-transport layer to extract positive charges from this sub-cell. However, PEDOT:PSS suffers from a high degree of parasitic light absorption, robbing the underlying bottom cell of valuable incoming photons. Furthermore, its highly acidic and hygroscopic nature chemically degrades the sensitive perovskite material, creating a critical compromise between efficiency and device lifespan.

This results in a severe material trade-off, whereby a layer intended to extract electric charge ends up blocking the very light needed to generate that charge, all while slowly destroying the underlying solar cell structure.

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To move away from PEDOT:PSS, researchers have frequently looked to SAMs, molecularly engineered alternatives that perform exceptionally well in pure lead-based perovskites. Yet, when deposited directly onto tin-lead perovskite layers, SAMs present an unexpected physical anomaly, triggering severe internal electrical field screening and inducing uneven grain growth at the buried interface. Using fast-hysteresis measurements and bias-assisted charge extraction measurements, the HZB team discovered that standard carbazole-based SAMs lead to massive ion accumulation, which severely hinders the cell’s ability to separate and extract photogenerated charge carriers.

Unlocking charge flow with a molecular bilayer

Led by Steve Albrecht, the HZB team designed a synergistic bilayer to circumvent this destructive ion accumulation and field-screening mechanism. They deposited an ultrathin, uniform layer of hydrophilic graphene oxide directly onto the transparent indium tin oxide conductive base, before introducing a specialized SAM molecule, MeO-2PACz. The phosphonic acid head groups of the SAM anchor strongly onto the oxygen-containing functional groups of the graphene oxide via hydrogen and covalent bonding.

This chemical arrangement prompts a favourable molecular reorientation that deepens the layer’s electronic work function, markedly enhancing its electrical conductivity. Additionally, the graphene oxide provides a smooth, hydrophilic foundation that accelerates crystal nucleation, generating a uniform, high-quality perovskite film completely free of the microscopic empty spaces (nanovoids) that plague SAM-only devices in this study.

When integrated into single-junction tin-lead solar cells, the new bilayer achieved a standalone power conversion efficiency of 22.1%, heavily outpacing the 12.0% efficiency of SAM-only equivalents. Using optoelectronic characterization, the team confirmed that this massive improvement was driven almost entirely by the mitigation of internal electronic and ionic extraction losses.

Record stability and the path to 30%

The researchers demonstrated the true potential of this technique when they integrated the bilayer into a monolithic triple-junction stack featuring sub-cells with band gaps of 2.00, 1.60 and 1.25 eV. By replacing the conventional gold and PEDOT:PSS interconnecting layers with an optimized indium tin oxide and graphene oxide/SAM bilayer configuration, they minimized parasitic light absorption in the near-infrared spectrum. This structural optimization raised the short-circuit current density of the narrow-band-gap bottom cell to 10.3 mA/cm², driving the overall triple-junction efficiency to 27.3%.

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Beyond the efficiency milestone, the chemically benign and robust nature of the graphene oxide/SAM interface yielded exceptional longevity. While traditional PEDOT:PSS-based cells degrade rapidly due to chemical interactions, the encapsulated bilayer devices successfully retained 90% of their initial performance after 770 h of continuous operational tracking under 1-sun illumination at room temperature. This sets a new stability record for triple-junction all-perovskite configurations.

The team notes that the current triple-junction performance is still bound by slight current mismatches and series-resistance transport losses across the interconnecting sub-cell junctions. By further optimizing the quality of the wider-band-gap perovskite layers and fine-tuning the band alignments of the intermediate contacts, the researchers project that the efficiency of this multi-junction solar architecture can comfortably clear the 30% barrier in the near future.

The solar cell design is detailed in Joule.

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Word flower puzzle no. 8

No Author — Wed, 09 Sep 2026 13:30:42 +0000

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+ + +

How did you get on?

28 words Warming up nicely

38 words Getting hot, hot, hot

48 words Top dog!

Fancy some more? Check out our puzzles page.

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Universities should judge quantum-computing investments by what students learn

No Author — Wed, 09 Sep 2026 10:00:02 +0000

The best moment in my quantum-computing class often comes when something fails. A student writes a short quantum circuit – a program that tells qubits what operations to perform – then runs it on an ideal simulator and gets the clean answer theory predicts. Yet when the same circuit runs on real quantum hardware, unexpected results appear.

What once looked certain now becomes messy. The student may think the machine has failed but this is, in fact, when the real lesson begins. A run on a quantum processor is a physical experiment that produces a computational result.

Quantum education is expanding rapidly. A recent analysis of course catalogues from 1456 US institutions identified more than 8000 courses the titles or descriptions of w hich mentioned “quantum”. That growth is welcome, but it also carries a risk. Many students on such courses first meet quantum computing as a perfect cartoon: ideal qubits, flawless gates and clean probabilities.

Such idealization can be useful with computer simulators – ordinary software that imitates a quantum computer without real qubits. Simulators make excellent first classroom tools because they let students grasp three basic quantum ideas: superposition, where several outcomes remain possible before measurement; interference, where those possibilities strengthen or cancel one another; and entanglement, where two qubits become linked so measuring one helps predict the other.

Students should feel the shock of an imperfect result

I will be honest; I have a love–hate relationship with patents or at least the process of obtaining them. As a scientist or engineer, it’s easy to think all the hard work is getting an invention over the line, slogging your guts out in the lab. But applying for a patent can be just as expensive and time-consuming, which is why you need to be clear on what and when to patent. Even Edison grew tired of being hailed a genius, stating that his success was “1% inspiration and 99% perspiration”.

Still, without the sweat of patents, your success might be all but 99% aspiration.

The post The pros and cons of patenting appeared first on Physics World.

Simulators also let students debug code and see the mathematics clearly. That matters in my classroom, because many students arrive with more confidence in Python than in quantum mechanics.

Useful as those abstractions are, they are not enough: students should learn not only the algorithm but also the machine that runs it. Real hardware exposes the gap between an ideal circuit and a physical device. A qubit is not a tiny coin showing heads and tails at once. It is a fragile physical system that gives different answers with varying probabilities when measured. Qubits lose information, gates make small mistakes, measurements misread states and nearby qubits can disturb one another.

The educational goal is to connect a quantum circuit to a real device – one in the lab, or one reached through the cloud. Yet that same circuit can behave differently after a recalibration, or after the device has “drifted”.

Students should see this as soon as possible. Teaching noise early shows students that quantum computing is an experimental science. If universities buy or rent quantum computers merely so that students can press “run”, they miss the best part of the lesson.

Intel inside

At Florida International University, this view shapes how I teach quantum computing. My students use Python, Qiskit, Jupyter notebooks, simulations and cloud quantum systems. My students have cloud access to an IonQ quantum computer that uses trapped-ion qubits, charged atoms confined by electromagnetic fields and manipulated with lasers. For now, our teaching uses cloud access to a quantum processing unit (QPU), raising a useful question: what does that access teach well, and what does it hide?

What cloud access teaches best is comparison. Students can run the same circuit on a simulator and a real QPU, then ask why the histograms – bar charts of measured output strings – differ. On platforms that expose device details, students can compare connectivity maps and calibration data such as coherence times, readout error rates and gate error rates.

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Cloud systems, however, can still hide too much. A polished interface can make a QPU look like a web service rather than a delicate machine. Students may not see the lasers that control ions or atoms, the cryostat that cools a superconducting chip, the microwave electronics that drive gates, or the human work behind calibration, where engineers tune the machine to keep it reliable. Cloud access teaches students to submit and analyse circuits. Access to hardware, control settings and error data helps them understand how the processor operates.

On-campus systems matter when students can inspect what sits behind the screen. In 2024 Rensselaer Polytechnic Institute in New York became the first university campus to host an IBM Quantum System One, initially powered by a 127-qubit Eagle processor. It is a striking example of a university putting a major machine within students’ reach.

Yet the educational value of any system depends less on qubit count than on what students can inspect, control and measure. A modest, accessible teaching platform – such as a photonic testbed that uses light to process information, a cryogenic set-up for testing devices at extremely low temperatures or a control-electronics lab that shows how signals drive qubits – can often teach more than a larger system that students cannot inspect.

Universities then should judge quantum-computing investments by learning outcomes, not headlines. Can students compare simulation and hardware? Can they test how a quantum computer changes over time by running the same circuit in the morning, afternoon and again the next day? Can they keep a notebook of circuits that worked in simulation but failed on hardware? Can they explain why one qubit pair works better than another? Can they connect algorithms to measurement, control, optics, microwaves, cryogenics and error reduction?

The experience has an emotional dimension too: a beautiful circuit on the whiteboard can become a difficult experiment on the chip. Students need to ask, “What algorithm did I write, and what physical experiment did the machine actually run?”

Students should feel the shock of an imperfect result, the frustration of a circuit that should have worked and the satisfaction of tracking down the physical cause. That experience turns quantum computing from a diagram into a craft.

A university quantum computer should be a teaching instrument that reveals the machine behind the calculation. Its purpose is to train people who can question claims, understand the hardware, and build the technology with sound judgement. The field needs graduates who understand the algorithm, the machine and the gap between them.

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Practical impurity analysis for biogas producers

Lorna Brigham — Mon, 02 Feb 2026 08:41:31 +0000

Biogas is a renewable energy source formed when bacteria break down organic materials such as food waste, plant matter, and landfill waste in an oxygen‑free (anaerobic) process. It contains methane and carbon dioxide, along with trace amounts of impurities. Because of its high methane content, biogas can be used to generate electricity and heat, or to power vehicles. It can also be upgraded to almost pure methane, known as biomethane, which can directly replace natural fossil gas.

Strict rules apply to the amount of impurities allowed in biogas and biomethane, as these contaminants can damage engines, turbines, and catalysts during upgrading or combustion. EN 16723 is the European standard that sets maximum allowable levels of siloxanes and sulfur‑containing compounds for biomethane injected into the natural gas grid or used as vehicle fuel. These limits are extremely low, meaning highly sensitive analytical techniques are required. However, most biogas plants do not have the advanced equipment needed to measure these impurities accurately.

Researchers from the Paul Scherrer Institute, Switzerland: Julian Indlekofer (left) and Ayush Agarwal (right), with the Liquid Quench Sampling System (Courtesy: Markus Fischer/Paul Scherrer Institute PSI)

The researchers developed a new, simpler method to sample and analyse biogas using GC‑ICP‑MS. Gas chromatography (GC) separates chemical compounds in a gas mixture based on how quickly they travel through a column. Inductively Coupled Plasma Mass Spectrometry (ICP‑MS) then detects the elements within those compounds at very low concentrations. Crucially, this combined method can measure both siloxanes and sulfur compounds simultaneously. It avoids matrix effects that can limit other detectors and cause biased or ambiguous results. It also achieves the very low detection limits required by EN 16723.

The sampling approach and centralized measurement enables biogas plants to meet regulatory standards using an efficient, less complex, and more cost‑effective method with fewer errors. Overall, this research provides a practical, high‑accuracy tool that makes reliable biogas impurity monitoring accessible to plants of all sizes, strengthening biomethane quality, protecting infrastructure, and accelerating the transition to cleaner energy systems.

+ https://physicsworld.com/?p=130087 + A new AI approach shows how batteries and hydrogen can improve renewable energy reliability

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Cavity-based X-ray laser delivers high-quality pulses

Hamish Johnston — Sat, 31 Jan 2026 15:00:06 +0000

Physicists in Germany have created a new type of X-ray laser that uses a resonator cavity to improve the output of a conventional X-ray free electron laser (XFEL). Their proof-of-concept design delivers X-ray pulses that are more monochromatic and coherent than those from existing XFELs.

In recent decades, XFELs have delivered pulses of monochromatic and coherent X-rays for a wide range of science including physics, chemistry, biology and materials science.

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Despite their name, XFELs do not work like conventional lasers. In particular, there is no gain medium or resonator cavity. Instead, XFELs rely on the fact that when a free electron is accelerated, it will emit electromagnetic radiation. In an XFEL, pulses of high-energy electrons are sent through an undulator, which deflects the electrons back and forth. These wiggling electrons radiate X-rays at a specific energy. As the X-rays and electrons travel along the undulator, they interact in such a way that the emitted X-ray pulse has a high degree of coherence.

While these XFELs have proven very useful, they do not deliver radiation that is as monochromatic or as coherent as radiation from conventional lasers. One reason why conventional lasers perform better is that the radiation is reflected back and forth many times in a mirrored cavity that is tuned to resonate at a specific frequency – whereas XFEL radiation only makes one pass through an undulator.

Practical X-ray cavities, however, are difficult to create. This is because X-rays penetrate deep into materials, where they are usually absorbed – making reflection with conventional mirrors impossible.

Crucial overlap

Now, researchers working at the European XFEL at DESY in Germany have created a proof-of-concept hybrid system that places an undulator within a mirrored resonator cavity. X-ray pulses that are created in the undulator are directed at a downstream mirror and reflected back to a mirror upstream of the undulator. The X-ray pulses are then reflected back downstream through the undulator. Crucially, a returning X-ray pulse overlaps with a subsequent electron pulse in the undulator, amplifying the X-ray pulse. As a result, the X-ray pulses circulating within the cavity quickly become more monochromatic and more coherent than pulses created by an undulator alone.

The team solved the mirror challenge by using diamond crystals that achieve the Bragg reflection of X-rays with a specific frequency. These are used at either end of the cavity in conjunction with Kirkpatrick–Baez mirrors, which help focus the reflected X-rays back into the cavity.

Some of the X-ray radiation circulating in the cavity is allowed to escape downstream, providing a beam of monochromatic and coherent X-ray pulses. They have called their system X-ray Free-Electron Laser Oscillator (XFELO). The cavity is about 66 m long.

Narrow frequency range

DESY accelerator scientist Patrick Rauer explains, “With every round trip, the noise in the X-ray pulse gets less and the concentrated light more defined”. Rauer pioneered the design of the cavity in his PhD work and is now the DESY lead on its implementation. “It gets more stable and you start to see this single, clear frequency – this spike.” Indeed, the frequency width of XFELO X-ray pulses is about 1% that of pulses that are created by the undulators alone

Ensuring the overlap of electron and X-pulses within the cavity was also a significant challenge. This required a high degree of stability within the accelerator that provides electron pulses to XFELO. “It took years to bring the accelerator to that state, which is now unique in the world of high-repetition-rate accelerators”, explains Rauer.

Team member Harald Sinn says, “The successful demonstration shows that the resonator principle is practical to implement”. Sinn is head of European XFEL’s instrumentation department and he adds, “In comparison with methods used up to now, it delivers X-ray pulses with a very narrow wavelength as well as a much higher stability and coherence.”

The team will now work towards improving the stability of XFELO so that in the future it can be used to do experiments by European XFEL’s research community.

XFELO is described in Nature.

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+ Real-number quantum theory can be more wrong than you thought + https://physicsworld.com/a/real-number-quantum-theory-can-be-more-wrong-than-you-thought/ + Wed, 09 Sep 2026 09:29:06 +0000 + + + https://physicsworld.com/?p=130258 + Imaginary numbers first appeared in the 16th century as a mathematical invention, introduced to solve equations that real numbers could not. As the name implies, many treated them as kind of trick to get results, rather than an underlying truth about the nature of reality. Although highly controversial at the time, these numbers are now ubiquitous […]

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The physics of an unethical daycare model that uses illness to maximize profits

Michael Banks — Fri, 30 Jan 2026 14:07:26 +0000

When I had two kids going through daycare, or nursery as we call it in the UK, every day seemed like a constant fight with germs and illness. After all, at such a young age kids still have a developing immune system and are not exactly hot on personal hygiene.

That same dilemma faced mathematician Lauren Smith from the University of Auckland. She has two children at a “wonderful daycare centre” who often fall ill. As many parents juggling work and parenting will understand, Smith is frequently faced with the issue of whether her kids are well enough to attend daycare.

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Smith then thought about how an unethical daycare centre might take advantage of this to maximize its profits – under the assumption that if there are not enough children attending (who still pay) then staff get sent home without pay, and also don’t get sick pay themselves.

“It occurred to me that a sick kid attending daycare could actually be financially beneficial to the centre, while clearly being a detriment to the wellbeing of the other children as well as the staff and the broader community,” Smith told Physics World.

For a hypothetical daycare centre that is solely focused on making as much money as possible, Smith realized that full attendance of sick children is not optimal financially as this requires maximal staffing at all times, whereas zero attendance of sick children does not give an opportunity for the disease to spread such that other children are then sent home.

But in between these two extremes, Smith thought there should be an optimal attendance rate so that the disease is still able to spread and some children – and staff – are sent home. “As a mathematician I knew I had the tools to find it,” adds Smith.

Model behaviour

Using the so-called Susceptible-Infected-Recovered model for 100 children, a teacher to child ratio of 1:6 and a recovery rate from illness of 10 days, Smith found that the more infectious the disease, the lower the optimal attendance rate for sick children is, and so the more savings the unethical daycare centre can make.

In other words, the more infectious a disease, fewer ill children are required to attend to spread it around, and so can keep more of them – and importantly staff – at home while still making sure it still spreads to non-infected kids.

For a measles outbreak with a basic reproductive number of 12-18, for example, the model resulted in a potential staff saving of 90 working days, whereas for seasonal flu with a basic reproductive rate of 1.2 to 1.3, the potential staff savings is 4.4 days.

Smith writes in the paper that the work is “not intended as a recipe for unethical daycare centre” but is rather to illustrate the financial incentive that exists for daycare centres to propagate diseases among children, which would lead to more infections of at-risk populations in the wider community.

“I hope that as well as being an interesting topic, it can show that mathematics itself is interesting and is useful for describing the real world,” adds Smith.

The post The physics of an unethical daycare model that uses illness to maximize profits appeared first on Physics World.

+ Optical vortices provide a natural way to create topologies + https://physicsworld.com/a/optical-vortices-provide-a-natural-way-to-create-topologies/ + Wed, 09 Sep 2026 09:26:01 +0000 + + + https://physicsworld.com/?p=130257 + New work suggests that building nontrivial topologies around optical vortices could be a better strategy than engineering delicate polarisation patterns across an entire beam

The post Optical vortices provide a natural way to create topologies appeared first on Physics World.

Saving the Titanic: the science of icebergs and unsinkable ships

Margaret Harris — Fri, 30 Jan 2026 13:00:46 +0000

When the Titanic was built, her owners famously described her as “unsinkable”. A few days into her maiden voyage, an iceberg in the North Atlantic famously proved them wrong. But what if we could make ships that really are unsinkable? And what if we could predict exactly how long a hazardous iceberg will last before it melts?

These are the premises of two separate papers published independently this week by Chunlei Guo and colleagues at the University of Rochester, and by Daisuke Noto and Hugo N Ulloa of the University of Pennsylvania, both in the US. The Rochester group’s paper, which appears in Advanced Functional Materials, describes how applying a superhydrophobic coating to an open-ended metallic tube can make it literally unsinkable – a claim supported by extensive tests in a water tank. Noto and Ulloa’s research, which they describe in Science Advances, likewise involved a water tank. Theirs, however, was equipped with cameras, lasers and thermochromic liquid crystals that enabled them to track a freely floating miniature iceberg as it melted.

Imagine a spherical iceberg

Each study is surprising in its own way. For the iceberg paper, arguably the biggest surprise is that no-one had ever done such experiments before. After all, water and ice are readily available. Fancy tanks, lasers, cameras and temperature-sensitive crystals are less so, yet surely someone, somewhere, must have stuck some ice in a tank and monitored what happened to it?

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Noto and Ulloa’s answer is, in effect, no. “Despite the relevance of melting of floating ice in calm and energetic environments…most experimental and numerical efforts to examine this process, even to date, have either fixed or tightly constrained the position and posture of ice,” they write. “Consequently, the relationships between ice dissolution rate and background fluid flow conditions inferred from these studies are meaningful only when a one-way interaction, from the liquid to the solid phase, dominates the melting dynamics.”

The problem, they continue, is that eliminating these approximations “introduces a significant technical challenge for both laboratory experiments and numerical simulations” thanks to a slew of interactions that would otherwise get swept under the rug. These interactions, in turn, lead to complex dynamics such as drifting, spinning and even flipping that must be incorporated into the model. Consequently, they write, “fundamental questions persist: ‘How long does an ice body last?’”

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Tracking a melting iceberg: This side view of the experiment shows fluid motions as moving particles and temperature distributions as colours of the thermochromic liquid crystal particles. Meltplume (dark colour) formed beneath the floating ice plunges down, penetrating through the thermally stratified layer (red: cold, blue: warm). Note: this video has no sound. (Courtesy: Noto and Ulloa, Science Advances 12 5 DOI: 10.1126/sciadv.ady352)

To answer this question, Noto and Ulloa used their water-tank observations (see video) to develop a model that incorporates the thermodynamics of ice melting and mass balance conservation. Based on this model, they correctly predict both the melting rate and the lifespan of freely floating ice under self-driven convective flows that arise from interactions between the ice and the calm, fresh water surrounding it. Though the behaviour of ice in tempestuous salty seas is, they write, “beyond our scope”, their model nevertheless provides a useful upper bound on iceberg longevity, with applications for climate modelling as well as (presumably) shipping forecasts for otherwise-doomed ocean liners.

The tube that would not sink

In the unsinkable tube study, the big surprise is that a metal tube, divided in the middle but open at both ends, can continue to float after being submerged, corroded with salt, tossed about on a turbulent sea and peppered with holes. How is that even possible?

“The inside of the tube is superhydrophobic, so water can’t enter and wet the walls,” Guo explains. “As a result, air remains trapped inside, providing buoyancy.”

Importantly, this buoyancy persists even if the tube is damaged. “When the tube is punctured, you can think of it as becoming two, three, or more smaller sections,” Guo tells Physics World. “Each section will work in the same way of preventing water from entering inside, so no matter how many holes you punch into it, the tube will remain afloat.”

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So, is there anything that could make these superhydrophobic structures sink? “I can’t think of any realistic real-world challenges more severe than what we have put them through experimentally,” he says.

We aren’t in unsinkable ship territory yet: the largest structure in the Rochester study was a decidedly un-Titanic-like raft a few centimetres across. But Guo doesn’t discount the possibility. He points out that tubes are made from ordinary aluminium, with a simple fabrication process. “If suitable applications call for it, I believe [human-scale versions] could become a reality within a decade,” he concludes.

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+ Cling film helps stamp two-dimensional materials onto patterned surfaces + https://physicsworld.com/a/cling-film-helps-stamp-two-dimensional-materials-onto-patterned-surfaces/ + Wed, 09 Sep 2026 08:00:37 +0000 + + + + https://physicsworld.com/?p=130267 + An unexpected material comes to the rescue of 2D material transfer

The post Cling film helps stamp two-dimensional materials onto patterned surfaces appeared first on Physics World.

Scientists quantify behaviour of micro- and nanoplastics in city environments

No Author — Fri, 30 Jan 2026 09:00:12 +0000

Measuring atmospheric plastics Abundance and composition of microplastics (MP) and nanoplastics (NP) in aerosols and estimated fluxes across atmospheric compartments in semiarid (Xi’an) and humid subtropical (Guangzhou) urban environments. (TSP: total suspended particles) (Courtesy: Institute of Earth Environment, CAS)

Plastic has become a global pollutant concern over the last couple of decades: it is widespread in society, not often disposed of effectively, and generates both microplastics (1 µm to 5 mm in size) and nanoplastics (smaller than 1 µm) that have infiltrated many ecosystems – including being found inside humans and animals.

Over time, bulk plastics break down into micro- and nanoplastics through fragmentation mechanisms that create much smaller particles with a range of shapes and sizes. Their small size has become a problem because they are increasingly finding their way into waterways that pollute the environment, into cities and other urban environments, and are now even being transported to remote polar and high-altitude regions.

This poses potential health risks around the world. While the behaviour of micro- and nanoplastics in the atmosphere is poorly understood, it’s thought that they are transported by transcontinental and transoceanic winds, which causes the spread of plastic in the global carbon cycle.

However, the lack of data on the emission, distribution and deposition of atmospheric micro- and nanoplastic particles makes it difficult to definitively say how they are transported around the world. It is also challenging to quantify their behaviour, because plastic particles can have a range of densities, sizes and shapes that undergo physical changes in clouds, all of which affect how they travel.

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A global team of researchers has developed a new semi-automated microanalytical method that can quantify atmospheric plastic particles present in air dustfall, rain, snow and dust resuspension. The research was performed across two Chinese megacities, Guangzhou and Xi’an.

“As atmospheric scientists, we noticed that microplastics in the atmosphere have been the least reported among all environmental compartments in the Earth system due to limitations in detection methods, because atmospheric particles are smaller and more complex to analyse,” explains Yu Huang, from the Institute of Earth Environment of the Chinese Academy of Sciences (IEECAS) and one of the paper’s lead authors. “We therefore set out to develop a reliable detection technique to determine whether microplastics are present in the atmosphere, and if so, in what quantities.”

Quantitative detection

For this new approach, the researchers employed a computer-controlled scanning electron microscopy (CCSEM) system equipped with energy-dispersive X-ray spectroscopy to reduce human bias in the measurements (which is an issue in manual inspections). They located and measured individual micro- and nanoplastic particles – enabling their concentration and physicochemical characteristics to be determined – in aerosols, dry and wet depositions, and resuspended road dust.

“We believe the key contribution of this work lies in the development of a semi‑automated method that identifies the atmosphere as a significant reservoir of microplastics. By avoiding the human bias inherent in visual inspection, our approach provides robust quantitative data,” says Huang. “Importantly, we found that these microplastics often coexist with other atmospheric particles, such as mineral dust and soot – a mixing state that could enhance their potential impacts on climate and the environment.”

The method could detect and quantify plastic particles as small as 200 nm, and revealed airborne concentrations of 1.8 × 10⁵ microplastics/m³ and 4.2 × 10⁴ nanoplastics/m³ in Guangzhou and 1.4 × 10⁵ microplastics/m³and 3.0 × 10⁴ nanoplastics/m³ in Xi’an. This is two to six orders of magnitude higher for both microplastic and nanoplastic fluxes than reported previously via visual methods.

The team also found that the deposition samples were more heterogeneously mixed with other particle types (such as dust and other pollution particles) than aerosols and resuspension samples, which showed that particles tend to aggregate in the atmosphere before being removed during atmospheric transport.

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The study revealed transport insights that could be beneficial for investigating the climate, ecosystem and human health impacts of plastic particles at all levels. The researchers are now advancing their method in two key directions.

“First, we are refining sampling and CCSEM‑based analytical strategies to detect mixed states between microplastics and biological or water‑soluble components, which remain invisible with current techniques. Understanding these interactions is essential for accurately assessing microplastics’ climate and health effects,” Huang tells Physics World. “Second, we are integrating CCSEM with Raman analysis to not only quantify abundance but also identify polymer types. This dual approach will generate vital evidence to support environmental policy decisions.”

The research was published in Science Advances.

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+ Missing decay at BESIII points to long-sought glueball + https://physicsworld.com/a/missing-decay-at-besiii-points-to-long-sought-glueball/ + Tue, 08 Sep 2026 13:41:50 +0000 + + + + https://physicsworld.com/?p=130271 + Heavy particle could be dominated by gluons

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Michele Dougherty steps aside as president of the Institute of Physics

Michael Banks — Thu, 29 Jan 2026 15:00:26 +0000

Shrinking Young’s experiment (a) The classical double-slit experiment using light (slit spacing ~1 mm, propagation distance ~1 m). (b) Schematic of atomic-scale interference in which a pair of neighbouring silicon atomic columns act as a “double slit” for a focused electron probe (spacing 136 pm; crystal thickness ~10 nm; distance to detector ~10 cm). (Courtesy: Koudai Tabata/University of Tokyo)

For the first time, physicists in Japan have carried out an atomic-scale version of the double-slit experiment. Using an ultraprecise electron beam channelled along two adjacent columns of atoms in a crystal of silicon, Naoya Shibata and colleagues at the University of Tokyo observed clear interference fringes in electrons scattered by the atoms: fringes that persisted even at high temperature, thanks to correlations in the atoms’ thermal vibrations.

The double-slit experiment is perhaps the most iconic demonstration in quantum mechanics: showing how a single particle’s wavefunction interferes with itself as it passes through two slits at once, with a tangible impact on where the particle is ultimately observed.

In practical research, this effect is now routinely harnessed in electron, neutron and atom interferometers. By observing the interference fringes that it creates, researchers can extract valuable information about both the quantum matter wave and whatever object is doing the diffracting.

Recently, physicists have attempted to push double-slit interferometry all the way down to the atomic scale, replacing conventional slits with crystal lattices. When a moving electron encounters an atom in a crystal, it scatters across a range of angles – producing an outgoing spherical wave that’s mathematically identical to the diffraction pattern from a classical slit.

Since atoms in a crystal sit at such well-defined separations, any neighbouring pair of them could, in principle, act as a double-slit interferometer. In reality, however, the many repeated unit cells in a crystal mean the resulting interference fringes are washed out, making it difficult to isolate the signal from a single atomic pair.

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To address this challenge, Shibata’s team used the ultraprecise probe of a 4D scanning transmission electron microscope: an instrument designed to capture electron diffraction patterns with a pixellated detector. Fired into a pure silicon crystal at just the right orientation, the microscope’s precision let the researchers target two adjacent columns of aligned silicon atoms, separated by just 136 pm. As a result, the electron wave overlapped both columns, and no others.

“Our key idea was to use these two atomic columns as the two slits,” describes team member Takehito Seki. “By channelling the probe along both columns at once, we turned them into two coherent scattering sources – effectively making the crystal itself into an atomic-scale double-slit interferometer.”

At this scale, Shibata and Seki’s team created electron interference fringes some seven orders of magnitude smaller than in Thomas Young’s original double-slit experiment with light, first carried out in 1801.

Just as in a larger-scale experiment, these patterns encoded information about the crystal and the electron beam. But at this scale, the researchers could also detect the signature of individual phonon modes in the columns. Rather than destroying coherence as uncorrelated atomic motion would in a classical picture, these correlated vibrations between the two atomic columns kept them moving in sync, preserving the interference.

“In a which-path picture, relative motion of the two atomic columns makes the two electron pathways more distinguishable and reduces the interference, whereas correlated in-phase motion preserves coherence,” Shibata explains. As a result, distinct interference fringes remained visible across temperatures ranging from 300 to 900 K.

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The team’s results already point to how an atomic-scale double-slit experiment could offer new ways to measure phonon correlations directly between single pairs of atoms. But as Shibata explains, the possible applications could stretch much further.

“It also opens a route to probing local lattice dynamics at the scale of individual atomic bonds, including at interfaces and defects, where local lattice dynamics can strongly influence thermal transport,” he says. “In the long run, such atomic-scale insight could help inform better thermal management strategies for future chip technologies.”

The study is published in Nature.

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Noise that entangles may accelerate the dawn of quantum technologies

Maria Gragera Garcés — Mon, 07 Sep 2026 12:00:45 +0000

Qubits are delicate and often misbehave. A qubit’s advantage over an ordinary bit is that in addition to “0” or “1”, it can hold values of 0 and 1 at once, in a specific combination; that combination is what quantum algorithms actually run on. But any stray interaction with the surrounding world (a vibration, a stray field, a single errant photon) leaks out a bit of information about which state the qubit is in – and that’s enough to collapse the combination back into an ordinary, classical either/or state. Coupling to the environment leads to high decoherence, meaning high error rates, and is normally how we lose good quality qubits. As such, most of the engineering effort in quantum computing goes into avoiding this coupling.

Yet recently, a team at the Institute of Science and Technology Austria (ISTA), working with collaborators in Munich and Madrid, has defied this norm.

Writing in Physical Review X, Alejandro Andrés-Juanes, Johannes Fink and colleagues show that two superconducting transmon qubits, separated by a metre of coaxial cable, can settle into an entangled state by being exposed to the same quantum-correlated microwave field. Avoiding synchronized pulses, heralding, post-selection and feedback (techniques usually used to actively generate and verify entanglement, rather than to fix decoherence), the entanglement can be generated and maintained for as long as the field is on. In other words, the researchers have managed to exploit noise to generate entanglement, rather than losing their qubits to it.

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This idea of entangling by using fields belongs to a family of techniques known as dissipation engineering. “The common understanding is that the environment is bad, and it will decohere your qubits,” Andrés-Juanes tells Physics World. “The main idea [here] is that one can engineer a specific interaction with the environment that is not detrimental but – like in this case – prepares your qubits in an interesting state without you having to actively apply any action on the system.”

This proposal dates back more than 20 years, to work performed by Barbara Kraus and Ignacio Cirac, but this is its first experimental realization.

The correlated environment comes from a superconducting device (a Josephson parametric converter) that splits each pump photon into a pair of photons at gigahertz frequencies. The two photons of this pair are entangled with one another and each is sent down its own coaxial cable to one of the qubits, half a metre away in either direction.

Quantum research The lab at the Institute of Science and Technology Austria. (Courtesy: © ISTA)

Because the noise reaching the two qubits is correlated, relaxing into it does not scramble them (specifically, it does not wash out the fixed phase relationship between them, as independent noise on each qubit would). They settle instead into a superposition, for which absorbing a photon from the field and emitting one into it interfere destructively: “the destructive interference between a photon emission event in the first waveguide and a photon absorption process at the location of the second qubit,” as the authors explain.

Once there, the qubits stop evolving and the field passes through unchanged: the entangled state is dark, invisible to the very field that created it. What the experiment does, in effect, is convert the continuous-variable (CV) entanglement carried by the two microwave beams into ordinary entanglement between two conventional transmon qubits – “we obtain qubit entanglement from CV entanglement,” Andrés-Juanes confirms – with roughly a tenth of it inherited.

Most entanglement-distribution schemes deliver entanglement as events: a pulse sequence runs, a detector clicks, a pair is announced, and the state then decays until the sequence runs again. The author’s autonomous version could enable the elimination of this machinery.

“It removes a lot of overhead on the pulse sequences you need to run to get the entanglement,” says Andrés-Juanes, an advantage that’s expected to matter most at scale, since one correlated photon source can drive many pairs at once. “Another differential feature of this protocol is that the entanglement is ‘always on’ for when you need to use it. In active protocols, you would have to reinitialize the entangled state because it would decohere after a while.”

The practical limit of this setup is temperature: “We use microwave frequencies, which are only quantum at very low temperatures,” Andrés-Juanes explains. “The real limit in the separation is how big your dilution refrigerator is”, with the longest such link so far being 30 m, at ETH Zurich. He positions the work as an intermediate-distance technology rather than a long-distance one. At optical frequencies, the constraint would lift, though achieving the same strong qubit–waveguide coupling in an atomic system would be its own problem.

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For now, the numbers are modest: two qubits, entangled with a concurrence of just 0.10 (on a scale where 1 is a perfect pair), inheriting only about a tenth of the entanglement carried by the microwave beams. The group is working on a module with more than one qubit per node.

But critically, the idea is no longer theoretical. The team has now realised an entangled link that is always “there”, bringing us one step closer to distributed quantum computing (linking separate processors into one machine via entanglement), networked sensing (detectors sharing entanglement to jointly see what none could alone) and quantum repeaters (relay stations for long-distance quantum links, needed because a quantum state can’t be copied and amplified like a classical signal).

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Magnetism likely played a key role in early solar system formation

Tim Wogan — Mon, 07 Sep 2026 08:00:37 +0000

The oldest known solids in the solar system contain evidence that the protoplanetary disc that went on to form the planets around our Sun experienced a magnetic field stronger than the field on Earth today, new research suggests. Study of inclusions in a primordial meteorite called a carbonaceous chondrite indicates that magnetism needs to be considered in simulations of planet formation, and may even be the dominant factor.

When planetary systems condense, they initially form high-temperature molecular nebulae. These later cool and accrete into planets surrounding central stars – which, at some point, begin to undergo nuclear fusion. Even before this happens, however, the gas is highly ionized. “A good portion of the ionization is coming from the molecular cloud itself,” explains planetary scientist Cauê Borlina of Purdue University. “It’s a combination of radiation from space and high temperature.”

In any ionized system there is the potential for magnetic fields, but simulations of disc formation often take no account of them, partly as they remain poorly constrained: “It’s a lot easier to just crank up the gravity and use that as a way to match the accretion rate,” says Borlina.

The new study from Borlina and colleagues in the US, China and the UK provides an unprecedented peek at fields in the terrestrial planet-forming region in the first 500,000 years of the Solar System’s existence – before the Earth had formed – using calcium-aluminium-rich inclusions. These are the oldest known solar system solids, comprising minerals with extremely high melting points that are inclined to condense early. “It is very unlikely to get them at later stages,” says Borlina. Previous researchers have confirmed their ages using isotopic dating.

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Millions of years after these inclusions formed, they agglomerated with other protoplanetary material into planetesimals, some of which went on to form planets. Planetary scientists think the remaining material accreted to form the chondrites – which astronomers distinguish into several different types depending on their chemical composition. When they fall to Earth as chondrite meteorites, therefore, they provide a valuable glimpse into the solar system’s raw material.

Carbonaceous chondrites hold particular interest as they are thought to have the most primitive chemical compositions of all meteorites. The researchers studied calcium-aluminium inclusions in the 667 g Dominion Range 08006 carbonaceous chondrite discovered in Antarctica in 2008. Such inclusions had, until around 2010, been thought to contain no magnetic minerals. Borlina and colleagues, however, found that some – although not all – of the inclusions contained nanometre-scale amounts of ferromagnetic iron-nickel.

The researchers measured the thermoremanent magnetization of these iron-nickel grains (the field strength they experienced at the time when they cooled down through their “Curie temperature”, thereby fixing their own magnetism). In theory, this could be achieved by heating the sample above the Curie temperature, which for iron-nickel is about 1050 K, and measuring the field required to demagnetize it. Unfortunately, says Borlina, heating meteorites up in the laboratory tends to oxidize the materials extremely quickly, making reliably calibrated experiments very difficult.

Instead, the researchers used an established method called anhysteric remanent magnetization, concluding that the inclusions were exposed to fields of 150–600 µT when they cooled through the Curie temperature (the field on Earth today is around 30–60 µT). “This is good evidence that…you can’t just ignore magnetic fields,” says Borlina. “They need to be present in your simulations.”

The researchers are now studying other carbonaceous chondrites and other types of chondrite meteorites – some of which are thought to have formed in different regions of the protoplanetary disc – hoping to gain a fuller picture of how magnetism shapes disc evolution. “The idea was to put it out there that there’s this new inclusion that might hold magnetic carriers, and there’s a lot of work to be done,” says Borlina.

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Meenakshi Wadhwa of University of California, San Diego – who formerly directed the Center for Meteorite Studies at Arizona State University – describes the work as “genuinely significant”. First, she says, it provides the first definitive paleomagnetic signal from a carbonaceous chondrite. Second, the estimated field is multiple times previous estimates.

“Yes, the sample size is small (five inclusions from a single chondrite), but I think the authors make a reasonably solid argument for their conclusions,” she says. The next step, she concludes, “is to measure inclusions from other chondrite groups to see if the signal is reproducible, and to test whether it’s a real nebular record versus something very localized, specific to DOM 08006 or the carbonaceous chondrite reservoir. Beyond that…pinning down when and where inclusions acquired their magnetization will also be important.”

The research is published in Proceedings of the National Academy of Sciences.

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AI-based tool improves the quality of radiation therapy plans for cancer treatment

Hamish Johnston — Thu, 29 Jan 2026 13:36:18 +0000

This episode of the Physics World Weekly podcast features Todd McNutt, who is a medical physicist at Johns Hopkins University and the founder of Oncospace. In a conversation with Physics World’s Tami Freeman, McNutt explains how an artificial intelligence-based tool called Plan AI can help improve the quality of radiation therapy plans for cancer treatments.

As well as discussing the benefits that Plan AI brings to radiotherapy patients and cancer treatment centres, they examine its evolution from an idea developed by an academic collaboration to a clinical product offered today by Sun Nuclear, a US manufacturer of radiation equipment and software.

This podcast is sponsored by Sun Nuclear.

The post AI-based tool improves the quality of radiation therapy plans for cancer treatment appeared first on Physics World.

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Fancy some more? Check out our puzzles page.

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The Future Circular Collider is unduly risky – CERN needs a ‘Plan B’

No Author — Thu, 29 Jan 2026 09:00:22 +0000

Last November I visited the CERN particle-physics lab near Geneva to attend the 4th International Symposium on the History of Particle Physics, which focused on advances in particle physics during the 1980s and 1990s. As usual, it was a refreshing, intellectually invigorating visit. I’m always inspired by the great diversity of scientists at CERN – complemented this time by historians, philosophers and other scholars of science.

As noted by historian John Krige in his opening keynote address, “CERN is a European laboratory with a global footprint. Yet for all its success it now faces a turning point.” During the period under examination at the symposium, CERN essentially achieved the “world laboratory” status that various leaders of particle physics had dreamt of for decades.

By building the Large Electron Positron (LEP) collider and then the Large Hadron Collider (LHC), the latter with contributions from Canada, China, India, Japan, Russia, the US and other non-European nations, CERN has attracted researchers from six continents. And as the Cold War ended in 1989–1991, two prescient CERN staff members developed the World Wide Web, helping knit this sprawling international scientific community together and enable extensive global collaboration.

The LHC was funded and built during a unique period of growing globalization and democratization that emerged in the wake of the Cold War’s end. After the US terminated the Superconducting Super Collider in 1993, CERN was the only game in town if one wanted to pursue particle physics at the multi-TeV energy frontier. And many particle physicists wanted to be involved in the search for the Higgs boson, which by the mid-1990s looked as if it should show up at accessible LHC energies.

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Having discovered this long-sought particle at the LHC in 2012, CERN is now contemplating an ambitious construction project, the Future Circular Collider (FCC). Over three times larger than the LHC, it would study this all-important, mass-generating boson in greater detail using an electron–positron collider dubbed FCC-ee, estimated to cost $18bn and start operations by 2050.

Later in the century, the FCC-hh, a proton–proton collider, would go in the same tunnel to see what, if anything, may lie at much higher energies. That collider, the cost of which is currently educated guesswork, would not come online until the mid 2070s.

But the steadily worsening geopolitics of a fragmenting world order could make funding and building these colliders dicey affairs. After Russia’s expulsion from CERN, little in the way of its contributions can be expected. Chinese physicists had hoped to build an equivalent collider, but those plans seem to have been put on the backburner for now.

And the “America First” political stance of the current US administration is hardly conducive to the multibillion-dollar contribution likely required from what is today the world’s richest (albeit debt-laden) nation. The ongoing collapse of the rules-based world order was recently put into stark relief by the US invasion of Venezuela and abduction of its president Nicolás Maduro, followed by Donald Trump’s menacing rhetoric over Greenland.

While these shocking events have immediate significance for international relations, they also suggest how difficult it may become to fund gargantuan international scientific projects such as the FCC. Under such circumstances, it is very difficult to imagine non-European nations being able to contribute a hoped-for third of the FCC’s total costs.

But the mounting European populist right-wing parties are no great friends of physics either, nor of international scientific endeavours. And Europeans face the not-insignificant costs of military rearmament in the face of Russian aggression and likely US withdrawal from Europe.

So the other two thirds of the FCC’s many billions in costs cannot be taken for granted – especially not during the decades needed to construct its 91 km tunnel, 350 GeV electron–positron collider, the subsequent 100 TeV proton collider, and the massive detectors both machines require.

According to former CERN director-general Chris Llewellyn Smith in his symposium lecture, “The political history of the LHC“, just under 12% of the material project costs of the LHC eventually came from non-member nations. It therefore warps the imagination to believe that a third of the much greater costs of the FCC can come from non-member nations in the current “Wild West” geopolitical climate.

But particle physics desperately needs a Higgs factory. After the 1983 Z boson discovery at the CERN SPS Collider, it took just six years before we had not one but two Z factories – LEP and the Stanford Linear Collider – which proved very productive machines. It’s now been more than 13 years since the Higgs boson discovery. Must we wait another 20 years?

Other options

CERN therefore needs a more modest, realistic, productive new scientific facility – a “Plan B” – to cope with the geopolitical uncertainties of an imperfect, unpredictable world. And I was encouraged to learn that several possible ideas are under consideration, according to outgoing CERN director-general Fabiola Gianotti in her symposium lecture, “CERN today and tomorrow“.

Three of these ideas reflect the European Strategy for Particle Physics, which states that “an electron–positron Higgs factory is the highest-priority next CERN collider”. Two linear electron–positron colliders would require just 11–34 km of tunnelling and could begin construction in the mid-2030s, but would involve a fair amount of technical risk and cost roughly €10bn.

The least costly and risky option, dubbed LEP3, involves installing superconducting radio-frequency cavities in the existing LHC tunnel once the high-luminosity proton run ends. Essentially an upgrade of the 200 GeV LEP2, this approach is based on well-understood technologies and would cost less than €5bn but can reach at most 240 GeV. The linear colliders could attain over twice that energy, enabling research on Higgs-boson decays into top quarks and the triple-Higgs self-interaction.

Other proposed projects involving the LHC tunnel can produce large numbers of Higgs bosons with relatively minor backgrounds, but they can hardly be called “Higgs factories”. One of these, dubbed the LHeC, could only produce a few thousand Higgs bosons annually and would allow other important research on proton structure functions. Another idea is the proposed Gamma Factory, in which laser beams would be backscattered from LHC beams of partially stripped ions. If sufficient photon energies and intensity can be achieved, it will allow research on the γγ → H interaction. These alternatives would cost at most a few billion euros.

As Krige stressed in his keynote address, CERN was meant to be more than a scientific laboratory at which European physicists could compete with their US and Soviet counterparts. As many of its founders intended, he said, it was “a cultural weapon against all forms of bigoted nationalism and anti-science populism that defied Enlightenment values of critical reasoning”. The same logic holds true today.

In planning the next phase in CERN’s estimable history, it is crucial to preserve this cultural vitality, while of course providing unparalleled opportunities to do world-class science – lacking which, the best scientists will turn elsewhere.

I therefore urge CERN planners to be daring but cognizant of financial and political reality in the fracturing world order. Don’t for a nanosecond assume that the future will be a smooth extrapolation from the past. Be fairly certain that whatever new facility you decide to build, there is a solid financial pathway to achieving it in a reasonable time frame.

The future of CERN – and the bracing spirit of CERN – rests in your hands.

The post The Future Circular Collider is unduly risky – CERN needs a ‘Plan B’ appeared first on Physics World.

+ Astronomers discover unusual 10-sided atmospheric wave on Saturn + https://physicsworld.com/a/astronomers-discover-unusual-10-sided-atmospheric-wave-on-saturn/ + Fri, 04 Sep 2026 10:00:38 +0000 + + + + https://physicsworld.com/?p=130222 + Astronomers estimate the decagon-shaped wave may still be evolving

The post Astronomers discover unusual 10-sided atmospheric wave on Saturn appeared first on Physics World.

Ion-clock transition could benefit quantum computing and nuclear physics

Hamish Johnston — Wed, 28 Jan 2026 15:07:43 +0000

Nuclear effect The deformed shape of the ytterbium-173 nucleus (right) makes it possible to excite the clock transition with a relatively low-power laser. The same transition is forbidden (left) if the nucleus is not deformed. (Courtesy: Physikalisch-Technische Bundesanstalt (PTB))

An atomic transition in ytterbium-173 could be used to create an optical multi-ion clock that is both precise and stable. That is the conclusion of researchers in Germany and Thailand who have characterized a clock transition that is enhanced by the non-spherical shape of the ytterbium-173 nucleus. As well as applications in timekeeping, the transition could be used in quantum computing. Furthermore, the interplay between atomic and nuclear effects in the transition could provide insights into the physics of deformed nuclei.

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The ticking of an atomic clock is defined by the frequency of the electromagnetic radiation that is absorbed and emitted by a specific transition between atomic energy levels. These clocks play crucial roles in technologies that require precision timing – such as global navigation satellite systems and communications networks. Currently, the international definition of the second is given by the frequency of caesium-based clocks, which deliver microwave time signals.

Today’s best clocks, however, work at higher optical frequencies and are therefore much more precise than microwave clocks. Indeed, at some point in the future metrologists will redefine the second in terms of an optical transition – but the international metrology community has yet to decide which transition will be used.

Broadly speaking, there are two types of optical clock. One uses an ensemble of atoms that are trapped and cooled to ultralow temperatures using lasers; the other involves a single atomic ion (or a few ions) held in an electromagnetic trap. Clocks that use one ion are extremely precise, but lack stability; whereas clocks that use many atoms are very stable, but sacrifice precision.

Optimizing performance

As a result, some physicists are developing clocks that use multiple ions with the aim of creating a clock that optimizes precision and stability.

Now, researchers at PTB and NIMT (the national metrology institutes of Germany and Thailand respectively) have characterized a clock transition in ions of ytterbium-173, and have shown that the transition could be used to create a multi-ion clock.

“This isotope has a particularly interesting transition,” explains PTB’s Tanja Mehlstäubler – who is a pioneer in the development of multi-ion clocks.

The ytterbium-173 nucleus is highly deformed with a shape that resembles a rugby ball. This deformation affects the electronic properties of the ion, which should make it much easier to use a laser to excite a specific transition that would be very useful for creating a multi-ion clock.

Stark effect

This clock transition can also be excited in ytterbium-171 and has already been used to create a single-ion clock. However, excitation in a ytterbium-171 clock requires an intense laser pulse, which creates a strong electric field that shifts the clock frequency (called the AC Stark effect). This is a particular problem for multi-ion clocks because the intensity of the laser (and hence the clock frequency) can vary across the region in which the ions are trapped.

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To show that a much lower laser intensity can be used to excite the clock transition in ytterbium-173, the team studied a “Coulomb crystal” in which three ions were trapped in a line and separated by about 10 micron. They illuminated the ions with laser light that was not uniform in intensity across the crystal. They were able to excite the transition at a relatively low laser intensity, which resulted in very small AC Stark shifts between the frequencies of the three ions.

According to the team, this means that as many as 100 trapped ytterbium-173 ions could be used to create a clock that could be used as a time standard; to redefine the second; and also to make very precise measurements of the Earth’s gravitational field.

As well as being useful for creating an optical ion clock, this multi-ion capability could also be exploited to create quantum-computing architectures based on multiple trapped ions. And because the observed effect is a result of the shape of the ytterbium-173 nucleus, further studies could provide insights into nuclear physics.

The research is described in Physical Review Letters.

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The power of a poster

No Author — Wed, 28 Jan 2026 11:00:30 +0000

Most researchers know the disappointment of submitting an abstract to give a conference lecture, only to find that it has been accepted as a poster presentation instead. If this has been your experience, I’m here to tell you that you need to rethink the value of a good poster.

For years, I pestered my university to erect a notice board outside my office so that I could showcase my group’s recent research posters. Each time, for reasons of cost, my request was unsuccessful. At the same time, I would see similar boards placed outside the offices of more senior and better-funded researchers in my university. I voiced my frustrations to a mentor whose advice was, “It’s better to seek forgiveness than permission.” So, since I couldn’t afford to buy a notice board, I simply used drawing pins to mount some unauthorized posters on the wall beside my office door.

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Some weeks later, I rounded the corner to my office corridor to find the head porter standing with a group of visitors gathered around my posters. He was telling them all about my research using solar energy to disinfect contaminated drinking water in disadvantaged communities in Sub-Saharan Africa. Unintentionally, my illegal posters had been subsumed into the head porter’s official tour that he frequently gave to visitors.

The group moved on but one man stayed behind, examining the poster very closely. I asked him if he had any questions. “No, thanks,” he said, “I’m not actually with the tour, I’m just waiting to visit someone further up the corridor and they’re not ready for me yet. Your research in Africa is very interesting.” We chatted for a while about the challenges of working in resource-poor environments. He seemed quite knowledgeable on the topic but soon left for his meeting.

A few days later while clearing my e-mail junk folder I spotted an e-mail from an Asian “philanthropist” offering me €20,000 towards my research. To collect the money, all I had to do was send him my bank account details. I paused for a moment to admire the novelty and elegance of this new e-mail scam before deleting it. Two days later I received a second e-mail from the same source asking why I hadn’t responded to their first generous offer. While admiring their persistence, I resisted the urge to respond by asking them to stop wasting their time and mine, and instead just deleted it.

So, you can imagine my surprise when the following Monday morning I received a phone call from the university deputy vice-chancellor inviting me to pop up for a quick chat. On arrival, he wasted no time before asking why I had been so foolish as to ignore repeated offers of research funding from one of the college’s most generous benefactors. And that is how I learned that those e-mails from the Asian philanthropist weren’t bogus.

The gentleman that I’d chatted with outside my office was indeed a wealthy philanthropic funder who had been visiting our university. Having retrieved the e-mails from my deleted items folder, I re-engaged with him and subsequently received €20,000 to install 10,000-litre harvested-rainwater tanks in as many primary schools in rural Uganda as the money would stretch to.

Secret to success Kevin McGuigan discovered that one research poster can lead to generous funding contributions. (Courtesy: Antonio Jaen Osuna)

About six months later, I presented the benefactor with a full report accounting for the funding expenditure, replete with photos of harvested-rainwater tanks installed in 10 primary schools, with their very happy new owners standing in the foreground. Since you miss 100% of the chances you don’t take, I decided I should push my luck and added a “wish list” of other research items that the philanthropist might consider funding.

The list started small and grew steadily ambitious. I asked for funds for more tanks in other schools, a travel bursary, PhD registration fees, student stipends and so on. All told, the list came to a total of several hundred thousand euros, but I emphasized that they had been very generous so I would be delighted to receive funding for any one of the listed items and, even if nothing was funded, I was still very grateful for everything he had already done. The following week my generous patron deposited a six-figure-euro sum into my university research account with instructions that it be used as I saw fit for my research purposes, “under the supervision of your university finance office”.

In my career I have co-ordinated several large-budget, multi-partner, interdisciplinary, international research projects. In each case, that money was hard-earned, needing at least six months and many sleepless nights to prepare the grant submission. It still amuses me that I garnered such a large sum on the back of one research poster, one 10-minute chat and fewer than six e-mails.

So, if you have learned nothing else from this story, please don’t underestimate the power of a strategically placed and impactful poster describing your research. You never know with whom it may resonate and down which road it might lead you.

The post The power of a poster appeared first on Physics World.

+ + + + https://physicsworld.com/?p=130178 + Heat and fire may have caused the mass extinction of Cretaceous creatures

The post ‘Lid’ of asteroid dust smothered and burned the dinosaurs, say scientists appeared first on Physics World.

ATLAS narrows the hunt for dark matter

Lorna Brigham — Wed, 28 Jan 2026 09:04:03 +0000

Researchers at the ATLAS collaboration have been searching for signs of new particles in the dark sector of the universe, a hidden realm that could help explain dark matter. In some theories, this sector contains dark quarks (fundamental particles) that undergo a shower and hadronization process, forming long-lived dark mesons (dark quarks and antiquarks bound by a new dark strong force), which eventually decay into ordinary particles. These decays would appear in the detector as unusual “emerging jets”: bursts of particles originating from displaced vertices relative to the primary collision point.

Using 51.8 fb⁻¹ of proton–proton collision data at 13.6 TeV collected in 2022–2023, the ATLAS team looked for events containing two such emerging jets. They explored two possible production mechanisms, which are a vector mediator (Z′) produced in the s‑channel and a scalar mediator (Φ) exchanged in the t‑channel. The analysis combined two complementary strategies. A cut-based strategy relying on high-level jet observables, including track-, vertex-, and jet-substructure-based selections, enables a straightforward reinterpretation for alternative theoretical models. A machine learning approach employs a per-jet tagger using a transformer architecture trained on low-level tracking variables to discriminate emerging from Standard Model jets, maximizing sensitivity for the specific models studied.

No emerging‑jet signal excess was found, but the search set the first direct limits on emerging‑jet production via a Z′ mediator and the first constraints on t‑channel Φ production. Depending on the model assumptions, Z′ masses up to around 2.5 TeV and Φ masses up to about 1.35 TeV are excluded. These results significantly narrow the space in which dark sector particles could exist and form part of a broader ATLAS programme to probe dark quantum chromodynamics. The work sharpens future searches for dark matter and advances our understanding of how a dark sector might behave.

Read the full article

Search for emerging jets in pp collisions at √s = 13.6 TeV with the ATLAS experiment

The ATLAS Collaboration 2025 Rep. Prog. Phys. 88 097801

+ This episode of the Physics World Weekly podcast features two conversations. The first is with career consultant Alaina G Levine who gives advice on how to build a “unicorn career” in science, technology, engineering, and mathematics. Our second guest is the optics and artificial-intelligence researcher Janelle Shane who writes extensively about the absurd, and often hilarious, side of AI.

Levine’s latest book is called Create Your Unicorn Career and Shane writes about artificial intelligence on her blog AI Weirdness.

This podcast is supported by American Elements, the world’s leading manufacturer of engineered and advanced materials. The company’s ability to scale laboratory breakthroughs to industrial production has contributed to many of the most significant technological advancements since 1990 – including LED lighting, smartphones, and electric vehicles.

Do you want to learn more about this topic?

Dark matter and dark energy interactions: theoretical challenges, cosmological implications and observational signatures by B Wang, E Abdalla, F Atrio-Barandela and D Pavón (2016)

The post ATLAS narrows the hunt for dark matter appeared first on Physics World.

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How do bacteria produce entropy?

Paul Mabey — Wed, 28 Jan 2026 09:02:07 +0000

Scientists have measured antineutrino emissions from spent nuclear fuel for the first time, demonstrating that monitoring efforts need not stop when the reactors do. This is important because although independent nuclear safeguarding agencies have long used antineutrino emissions to glean information on reactor operations, previous detection schemes only worked when the reactors were running. Now, however, members of the Double Chooz collaboration have shown that it is possible to detect residual antineutrino emissions during a complete reactor shutdown – including from spent fuel stored in cooling pools.

Like neutrinos, antineutrinos are tiny, nearly massless fundamental particles that come in three flavours: electron, muon and tau. The largest human-made sources of electron antineutrinos are the reactor cores of nuclear power plants, which produce them via beta decay of neutron-rich fragments that are primarily generated during the fission of heavy elements such as uranium and plutonium.

Because antineutrinos interact so rarely with other particles, their emissions cannot be shielded and their signatures cannot be altered. They can also be detected some distance from the power plant itself. All these features make them valuable for nonintrusive nuclear reactor monitoring. Indeed, the idea of using antineutrinos to provide real-time information about the fissile content of a reactor core – and thereby detect illicit production of material that could be used in nuclear weapons manufacturing – dates back to the 1970s.

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When a reactor is shut down, long-lived fission products (found in burnt fuel assemblies that remain in the reactor core, as well as assemblies that were previously removed and stored in nearby cooling pools) continue to decay, producing a residual neutrino flux. However, this residual signal is only around 1% as strong as the signal from an operating reactor. It also lies in a region of the energy spectrum that is strongly affected by background activities.

Measuring the residual neutrino flux and its energy spectrum

In the new work, which is detailed in Physical Review Letters, a team led by Thierry Lasserre and Anthony Onillon from the Max-Planck-Institut für Kernphysik (MPIK) in Heidelberg, Germany, succeeded in measuring the residual neutrino flux and its energy spectrum despite these difficulties. They obtained their data from the Double Chooz neutrino detection experiment, which is located near the two 4.25 GWth cores of the Chooz B nuclear power plant in the French Ardennes. This experiment uses a pair of detectors – labelled “near” and “far” and located around 400 m and 1.05 km from the cores – to study a fundamental parameter called the 𝜃₁₃ neutrino mixing angle that describes how neutrinos transform between different types as they travel.

The Chooz plant uses a pair of pressurized water reactors, each of which contains 205 fuel assemblies consisting of roughly 600 kg of enriched uranium dioxide (mainly ²³⁸U with a few percent of ²³⁵U). During operation, these reactors also produce additional fissile isotopes, ²³⁹Pu and ²⁴¹Pu, through neutron capture and subsequent decay processes involving ²³⁸U. In a typical cycle, they operate at full power for over a year and are then shut down for six to eight weeks for refuelling. During this time, some of the spent fuel assemblies are removed and transferred to storage pools in a nearby building.

The Double Chooz neutrino detector consists of more than 30 m³ of liquid scintillator, which is a material that emits short, double flashes of light when an antineutrino hits it. The outer part of the detector is shielded from the background radiation of the surrounding mountain rocks by 15 cm of demagnetized steel for the far detector and 1 m of water for the near detector. The inner part of the detector is shielded by a thick layer of mineral oil. Finally, an outer “muon veto” consisting of segmented scintillator modules positioned above the detector eliminates contributions from cosmic muons that can mask the signal from the antineutrinos.

Over 100 events observed

The researchers collected their data in 2017 when both of Chooz’s reactors were simultaneously shut down for 24.4 days for refuelling and maintenance. This unusual double shutdown was long enough for the team to obtain the statistics and low background signals needed to extract, for the first time, a quantitative residual reactor antineutrino spectrum.

After accounting for muon veto-induced dead time, the researchers clocked up 17.2 days of measurements for the near detector and 22.2 days for the far detector. While they analysed data from both, they mainly focused on the near detector because it is closer to the reactor cores and spent fuel pools and is therefore more sensitive to the residual antineutrino flux.

In the 1–3 MeV range, where the residual neutrino signal is strongest, the researchers observed 106 ±18 events, which represents a 5.9 σ excess over the background. This value, they say, is in very good agreement with the 88 ±7 events predicted by detailed simulations of the remaining nuclear fuel inventory and the decay of long-lived fission products.

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According to the researchers, this result had a long gestation period: “In 2003, the IAEA safeguards met with the neutrino community and raised a question: could antineutrinos also provide information on spent nuclear fuel?

“The main difficulty has been detecting the faint residual antineutrino signal. This meant obtaining data during periods when both Chooz reactors were simultaneously off, very low and well-controlled detector backgrounds, and a detailed simulation of the irradiation and cooling history of relevant fuel assemblies.”

The researchers hope that their result will become a robust benchmark for agencies and experimenters designing detectors for specific spent-fuel monitoring applications. “Such monitoring is feasible and could provide an independent, non-intrusive complement to reactor-status and spent fuel inventory,” they tell Physics World, though they add that “it will not necessarily be easy, compact or inexpensive to implement.”

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Einstein’s recoiling slit experiment realized at the quantum limit

Mira Varma — Wed, 28 Jan 2026 09:00:52 +0000

Quantum mechanics famously limits how much information about a system can be accessed at once in a single experiment. The more precisely a particle’s path can be determined, the less visible its interference pattern becomes. This trade-off, known as Bohr’s complementarity principle, has shaped our understanding of quantum physics for nearly a century. Now, researchers in China have brought one of the most famous thought experiments surrounding this principle to the quantum limit, using a single atom as a movable slit.

The thought experiment dates back to the 1927 Solvay Conference, where Albert Einstein proposed a modification of the double-slit experiment in which one of the slits could recoil. He argued that if a photon caused the slit to recoil as it passed through, then measuring that recoil might reveal which path the photon had taken without destroying the interference pattern. Conversely, Niels Bohr argued that any such recoil would entangle the photon with the slit, washing out the interference fringes.

For decades, this debate remained largely philosophical. The challenge was not about adding a detector or a label to track a photon’s path. Instead, the question was whether the “which-path” information could be stored in the motion of the slit itself. Until now, however, no physical slit was sensitive enough to register the momentum kick from a single photon.

A slit that kicks back

To detect the recoil from a single photon, the slit’s momentum uncertainty must be comparable to the photon’s momentum. For any ordinary macroscopic slit, its quantum fluctuations are significantly larger than the recoil, washing out the which-path information. To give a sense of scale, the authors note that even a 1 g object modelled as a 100 kHz oscillator (for example, a mirror on a spring) would have a ground-state momentum uncertainty of about 10^-16 kg m s^-1, roughly 11 orders of magnitude larger than the momentum of an optical photon (approximately 10^-27 kg m s^-1).

Experimental realization To perform Einstein’s thought experiment in the lab, the researchers used a single trapped atom as a movable slit. Photon paths become correlated with the atom’s motion, allowing researchers to probe the trade-off between interference and which-path information. (Courtesy: Y-C Zhang et al. Phys. Rev. Lett. 135 230202)

In their study, published in Physical Review Letters, Yu-Chen Zhang and colleagues from the University of Science and Technology of China overcame this obstacle by replacing the movable slit with a single rubidium atom held in an optical tweezer and cooled to its three-dimensional motional ground state. In this regime, the atom’s momentum uncertainty reaches the quantum limit, making the recoil from a single photon directly measurable.

Rather than using a conventional double-slit geometry, the researchers built an optical interferometer in which photons scattered off the trapped atom. By tuning the depth of this optical trap, the researchers were able to precisely control the atom’s intrinsic momentum uncertainty, effectively adjusting how “movable” the slit was.

Watching interference fade

As the researchers decreased the atom’s momentum uncertainty, they observed a loss of interference in the scattered photons. Increasing the atom’s momentum uncertainty caused the interference to reappear.

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This behaviour directly revealed the trade-off between interference and which-path information at the heart of the Einstein–Bohr debate. The researchers note that the loss of interference arose not from classical noise, but from entanglement between the photon and the atom’s motion.

“The main challenge was matching the slit’s momentum uncertainty to that of a single photon,” says corresponding author Jian-Wei Pan. “For macroscopic objects, momentum fluctuations are far too large – they completely hide the recoil. Using a single atom cooled to its motional ground state allows us to reach the fundamental quantum limit.”

Maintaining interferometric phase stability was equally demanding. The team used active phase stabilization with a reference laser to keep the optical path length stable to within a few nanometres (roughly 3 nm) for over 10 h.

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Beyond settling a historical argument, the experiment offers a clean demonstration of how entanglement plays a key role in Bohr’s complementarity principle. As Pan explains, the results suggest that “entanglement in the momentum degree-of-freedom is the deeper reason behind the loss of interference when which-path information becomes available”.

This experiment opens the door to exploring quantum measurement in a new regime. By treating the slit itself as a quantum object, future studies could probe how entanglement emerges between light and matter. Additionally, the same set-up could be used to gradually increase the mass of the slit, providing a new way to study the transition from quantum to classical behaviour.

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+ Plasmonic metamaterial makes a photonic time crystal + https://physicsworld.com/a/plasmonic-metamaterial-makes-a-photonic-time-crystal/ + Thu, 03 Sep 2026 08:00:02 +0000 + + + + https://physicsworld.com/?p=130169 + New nanostructure could be used to make lasers that work in the terahertz frequency range

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European Space Agency unveils first images from Earth-observation ‘sounder’ satellite

Michael Banks — Tue, 27 Jan 2026 18:26:07 +0000

The European Space Agency has released the first images from the Meteosat Third Generation-Sounder (MTG-S) satellite. They show variations in temperature and humidity over Europe and northern Africa in unprecedented detail with further data from the mission set to improve weather-forecasting models and improve measurements of air quality over Europe.

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Launched on 1 July 2025 from the Kennedy Space Center in Florida aboard a SpaceX Falcon 9 rocket, MTG-S operates from a geostationary orbit, about 36 000 km above Earth’s surface and is able to provide coverage of Europe and part of northern Africa on a 15-minute repeat cycle.

The satellite carries a hyperspectral sounding instrument that uses interferometry to capture data on temperature and humidity as well as being able to measure wind and trace gases in the atmosphere. It can scan nearly 2,000 thermal infrared wavelengths every 30 minutes.

The data will eventually be used to generate 3D maps of the atmosphere and help improve the accuracy of weather forecasting, especially for rapidly evolving storms.

The “temperature” image, above, was taken in November 2025 and shows heat (red) from the African continent, while a dark blue weather front covers Spain and Portugal.

The “humidity” image, below, was captured using the sounder’s medium-wave infrared channel. Blue colours represent regions in the atmosphere with higher humidity, while red colours correspond to lower humidity.

(Courtesy: EUMETSAT)

“Seeing the first infrared sounder images from MTG-S really brings this mission and its potential to life,” notes Simonetta Cheli, ESA’s director of Earth observation programmes. “We expect data from this mission to change the way we forecast severe storms over Europe – and this is very exciting for communities and citizens, as well as for meteorologists and climatologists.”

ESA is expected to launch a second Meteosat Third Generation-Imaging satellite later this year following the launch of the first one – MTG-I1 – in December 2022.

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Uranus and Neptune may be more rocky than icy, say astrophysicists

Isabelle Dumé — Tue, 27 Jan 2026 13:00:47 +0000

Our usual picture of Uranus and Neptune as “ice giant” planets may not be entirely correct. According to new work by scientists at the University of Zürich (UZH), Switzerland, the outermost planets in our solar system may in fact be rock-rich worlds with complex internal structures – something that could have major implications for our understanding of how these planets formed and evolved.

Within our solar system, planets fall into three categories based on their internal composition. Mercury, Venus, Earth and Mars are deemed terrestrial rocky planets; Jupiter and Saturn are gas giants; and Uranus and Neptune are ice giants.

An agnostic approach

The new work, which was led by PhD student Luca Morf in UZH’s astrophysics department, challenges this last categorization by numerically simulating the two planets’ interiors as a mixture of rock, water, hydrogen and helium. Morf explains that this modelling framework is initially “agnostic” – meaning unbiased – about what the density profiles of the planets’ interiors should be. “We then calculate the gravitational fields of the planets so that they match with observational measurements to infer a possible composition,” he says.

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This process, Morf continues, is then repeated and refined to ensure that each model satisfies several criteria. The first criteria is that the planet should be in hydrostatic equilibrium, meaning that its internal pressure is enough to counteract its gravity and keep it stable. The second is that the planet should have the gravitational moments observed in spacecraft data. These moments describe the gravitational field of a planet, which is complex because planets are not perfect spheres.

The final criteria is that the modelled planets need to be thermodynamically and compositionally consistent with known physics. “For example, a simulation of the planets’ interiors must obey equations of state, which dictate how materials behave under given pressure and temperature conditions,” Morf explains.

After each iteration, the researchers adjust the density profile of each planet and test it to ensure that the model continues to adhere to the three criteria. “We wanted to bridge the gap between existing physics-based models that are overly constrained and empirical approaches that are too simplified,” Morf explains. Avoiding strict initial assumptions about composition, he says, “lets the physics and data guide the solution [and] allows us to probe a larger parameter space.”

A wide range of possible structures

Based on their models, the UZH astrophysicists concluded that the interiors of Uranus and Neptune could have a wide range of possible structures, encompassing both water-rich and rock-rich configurations. More specifically, their calculations yield rock-to-water ratios of between 0.04-3.92 for Uranus and 0.20-1.78 for Neptune.

Slices of different pies: According to models developed with “agnostic” initial assumptions, Uranus (top) and Neptune (bottom) could be composed mainly of water ice (blue areas), but they could also contain substantial amounts of silicon dioxide rock (brown areas). (Courtesy: Luca Morf)

The models, which are detailed in Astronomy and Astrophysics, also contain convective regions with ionic water pockets. The presence of such pockets could explain the fact that Uranus and Neptune, unlike Earth, have more than two magnetic poles, as the pockets would generate their own local magnetic dynamos.

Traditional “ice giant” label may be too simple

Overall, the new findings suggest that the traditional “ice giant” label may oversimplify the true nature of Uranus of Neptune, Morf tells Physics World. Instead, these planets could have complex internal structures with compositional gradients and different heat transport mechanisms. Though much uncertainty remains, Morf stresses that Uranus and Neptune – and, by extension, similar intermediate-class planets that may exist in other solar systems – are so poorly understood that any new information about their internal structure is valuable.

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A dedicated space mission to these outer planets would yield more accurate measurements of the planets’ gravitational and magnetic fields, enabling scientists to refine the limited existing observational data. In the meantime, the UZH researchers are looking for more solutions for the possible interiors of Uranus and Neptune and improving their models to account for additional constraints, such as atmospheric conditions. “Our work will also guide laboratory and theoretical studies on the way materials behave in general at high temperatures and pressures,” Morf says.

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+ Two-dimensional material shows promise for long-term memory, thanks to slow electrons + https://physicsworld.com/a/two-dimensional-material-shows-promise-for-long-term-memory-thanks-to-slow-electrons/ + Wed, 02 Sep 2026 14:30:19 +0000 + + + + https://physicsworld.com/?p=130160 + A 2D magnetic material exhibits a charge-ordered state in which electrons move collectively and unusually slowly while maintaining quantum coherence

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String-theory concept boosts understanding of biological networks

No Author — Tue, 27 Jan 2026 09:35:45 +0000

China has made astounding scientific progress over the past decade, with the country outperforming all others in the world according to a recent analysis by Nature. Based on data from 2025, its 2026 Research Leaders study puts China ahead of the US (in second), Germany (third) and the UK (fourth).

Across all disciplines, Nature reports that most (51) of the top 100 institutions in the world are in China, with only four in the UK. The picture is slightly different if you judge academic institutions based only on their work in the physical sciences, but China still has 30 of the top 100 institutions, with only seven from the UK.

Professional physicists may not care much for such league tables but they do reveal just how far China has come in recent years. The country’s scientific strength was particularly evident at the fourth International Congress of Basic Science (ICBS) in Beijing, which I recently attended.

Founded in 2023 by the Fields-medal-winning mathematician Shing-Tung Yau, this year’s ICBS ran from 9-21 August at the Beijing Institute of Mathematical Sciences and Applications (BIMSA), of which Yau is president. Its international character is evident from the fact that a total of 50 of its 140 full-time researchers are from outside China.

Awards and honours

Over 800 participants from more than 30 countries attended the congress, which had the theme “Advancing science for humanity”, with my participation supported by the organisers. The programme was huge, featuring over 500 academic sessions covering topics from generative AI reasoning to quantum information.

Nine scientists, including four women, were awarded an inaugural Basic Science Medal. They were Claire Voisin (algebraic gemoetry), Horng-Tzer Yau (probability theory), Shou-Wu Zhang (maths), Yifang Wang (particle physics), Xiao-Gang Wen (condensed matter), Andrea Liu (complex systems), Zhenan Bao (flexible electronics), Xiaowei Zhuang (imaging), and Feng Zhang (CRISPR co-discoverer).

Meanwhile, Frontiers of Science Awards were given to over 500 researchers from 20 countries who had done work of “excellent and of outstanding scholarly value” over the last 5-10 years in the three fields represented at the ICBS. Authors from many Chinese institutions were among the recipients, underscoring the growing international impact and vitality of China’s basic science research.

Youth focus Student nights wre held at the congress. (Courtesy: ICBS)

There were 20 plenary sessions, over 400 Frontiers of Science Awardee talks, plus events for entrepreneurs and school and university students. Especially engaging were the “nights of mathematics, physics and engineering”, enlivened by dance amd music performances by students. An exchange meeting was held too for research institutions in Beijing seeking to integrate basic science with frontier technologies

The closing ceremony saw the winners of this year’s ICBS Innovation Fellowships announced. They are all researchers under 50 who work full-time in China and have demonstrated potential in mathematics, physics, information sciences, and other fundamental and interdisciplinary fields. Each receives research funding and can work with a partner institution in China for an agreed period.

AI surges ahead

Artificial intelligence (AI) was one of the major themes of ICBS 2026. Fields medallist Martin Hairer from EPFL Lausanne, for example, said AI won’t end mathematics, but will transform how it’s carried out. It may speed up certain areas while others might fall away.

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Caucher Birkar from Tsinghua University – another Fields medallist – pointed out that AI is highly capable in computation, searching for examples, and completing proofs of mathematical lemmas, but it remains difficult for AI to generate truly original ideas.

As for Robert Endre Tarjan, a Turing award laureate from Princeton University, he encouraged young researchers to be curious and commit themselves to long-term scientific exploration. Researchers, he said, can train AI to be a powerful tool for scientific discovery, but they must also develop their own ability to identify meaningful questions and establish independent judgment.

The last word was left to congress chair Shing-Tung Yau, who emphasised that while AI will enhance scientific research, the essence of scientific discovery will always depend on human creativity, imagination and independent thinking.

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Breaking in: how ultrasound smuggles drugs past the blood–brain barrier

Henrietta Smith — Wed, 02 Sep 2026 08:00:18 +0000

Brain tumour images Representative MR images of baseline (left panels) and FUS-treated (right panels) mouse brains. The top row shows administration of a 2.3 nm contrast agent (MultiHance), the bottom row shows administered iron oxide nanoparticles, 45 nm in size. Each pair of panels shows the anatomic image with the tumour outlined in red on the left, and the corresponding image superimposed with a concentration map showing the amount of nanoparticle retained within the tumour (as a percentage of the injected dose per gram) on the right. (Courtesy: CC BY 4.0/Radiology 10.1148/radiol.251005)

Drug delivery to the brain has been a longstanding challenge in medicine. One option is focused ultrasound (FUS), which can safely disrupt the blood–brain barrier for drug delivery. But how much of a drug gets into the brain depends heavily on its size. A long-standing assumption is that delivery decreases as drug size increases. But by using a clever spin on MRI physics, researcher Matthew Hoch and colleagues from the University of Virginia have shown that “the smaller the better” might not be entirely correct.

The blood–brain barrier is one of biology’s toughest engineering problems. Composed of a dense, tightly sealed layer of cells lining every blood vessel in the brain, the blood–brain barrier only lets nutrients and oxygen through and protects the central nervous system by blocking bloodborne pathogens. In doing so, however, it also blocks the delivery of drugs to the brain. Brain tumours compound this with their own blood–tumour barrier, further hindering drug delivery. For years, researchers have pondered how therapeutics could be delivered past these checkpoints; the answer may simply lie in the use of sound.

The process begins with the injection of gas-filled microbubbles into the bloodstream, where they circulate freely. Exposure to FUS then expands and contracts the volume of these microbubbles, creating a temporary, localized gap that pries the barrier open just long enough for drugs to slip through. Although the technique works, it is unclear how much of a drug actually comes through. In this new study, the team investigate how the size of the drug influences FUS-mediated drug delivery and introduce a novel technique to measure precisely how much drug is delivered.

The measurement problem

Many neurotherapies, with a range of sizes, could benefit from this drug delivery method. But measuring how much of the drug gets past the blood–brain barrier is challenging with current imaging methods. For example, fluorescence imaging is limited by its semi-quantitative nature, while PET scanning suffers from poor spatial resolution.

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Standard MRI methods are not only time-consuming, but, in the form of T1-mapping, are typically limited by the size of commercially available contrast agents, which are small in comparison to larger neurotherapeutics used for immunotherapy and gene delivery. Other standard MRI methods sensitive to the presence of iron (T2-mapping) provide an alternative avenue to measure larger agents, but can again be limited by scan time for 3D visualization. Both approaches also have potential to suffer from low sensitivity at low concentrations.

Hoch and his team solve this measurement problem by introducing quantitative susceptibility mapping (QSM), an MRI technique with diverse applications in neuroimaging including evaluation of haemorrhage, iron deposition and calcification. QSM works by exploiting the distortion of local magnetic fields by different materials, a property called magnetic susceptibility. By injecting iron-based nanoparticles that induce measurable, spatially localized shifts in the MRI signal’s phase, QSM can generate a 3D map of magnetic susceptibility. This can then be used to calculate the actual concentration of iron-based nanoparticles within tissues.

By transforming an MRI scanner into a sensitive nanoparticle detector, the researchers present a novel way to quantify drug delivery down to fractions of a percent of the injected dose.

What did they find?

The team tested this approach using four different particles, with a 20-fold range in size. The first was a small gadolinium-based contrast agent, MultiHance (a proxy for small molecule therapeutics), at around 2.3 nm; the other three were iron oxide nanoparticles (IONPs) of 15, 23 and 45 nm, sizes that mirror the dimensions of therapeutic candidates used for immunotherapy and gene therapy.

Using healthy and glioma brain tumour-carrying mice, the researchers used FUS treatment to open the blood–brain barrier and deliver particles of varying sizes. They recorded MRI scans before and after delivery and used QSM to generate a precise measurement of how much of each particle made it into brain tissue.

Brain delivery by particle size The amount of drug delivered, as a percentage of the initial injected dose, that has successfully travelled to the brain. (Courtesy: Adapted from Radiology 10.1148/radiol.251005/CC BY 4.0)

The results were unexpected. Drug delivery followed a bell-shaped curve in healthy mice. From the smallest (2.3 nm) particle to the 15 nm IONP, delivery increased 2.6-fold, then at 23 nm, remained steady. Interestingly, at 45 nm, delivery dropped by 2.5-fold compared with the 23 nm nanoparticle, comparable to that of the smallest agent.

This sweet spot, ranging from 15 to 23 nm, demonstrates that smaller isn’t always better. The researchers suspect that this trend in drug delivery is due to a balance between how easily a particle can squeeze through the barrier (so favouring smaller particles) and how long a particle stays in circulation, giving it more time to travel across the barrier (favouring larger particles).

In the mice with brain tumours, where there is an addition of the tumour’s own leaky, disorganized vasculature, the blood–tumour barrier, drug delivery can differ from that to healthy brain. Specifically, this barrier is thought to make drug delivery more difficult than in healthy tissue due to higher tissue pressures and inconsistent blood flow. But the researchers unexpectedly found that FUS boosted delivery of both small and large agents into tumours, with no real difference to the drug delivery levels seen in healthy brain tissue, despite the added presence of the blood–tumour barrier.

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“The outcome is exciting because it means that focused ultrasound delivery performance is not expected to diminish in brain tumours,” says senior author Richard J Price in a press statement. “In fact, it may even be enhanced for some types of therapeutics.”

FUS-mediated barrier opening is currently in clinical trials for use in Alzheimer’s disease and glioblastoma, and this research has implications in both drug engineering and treatment planning. By introducing QSM, Hoch and his colleagues have provided a universal, precision technique to quantify contrast agent delivery. Taking existing tools, used for a specific physics measurement problem, and developing them to answer a completely different biological question is no small feat. Here, the researchers present an ingenious intersection of physics and biology, and its potential application in medicine.

The researchers report their findings in Radiology.

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The secret life of TiO₂ in foams

Lorna Brigham — Mon, 26 Jan 2026 16:31:27 +0000

When light is absorbed by a semiconductor, it first creates an electron-hole pair before free charges can be generated. The electron and hole can remain bound together in a quasiparticle known as an exciton. This intermediate stage is important because excitons determine how light is absorbed and emitted, and how efficiently a material can convert light into electrical current.

Monolayer tungsten diselenide (WSe₂) is a material that researchers are investigating for use in photodetectors, optical computing and quantum technologies. It is an atom-thick semiconductor that interacts very strongly with light. The excitons formed in WSe₂ are unusually stable, allowing quantum effects to be observed particularly strongly. WSe₂ therefore provides a model system for learning how to control light-generated excitons, knowledge that could eventually lead to more efficient solar cells, photodetectors and low-energy photonic technologies.

A key question in this area of research is what causes the WSe₂ exciton energy to shift to a higher energy (blue shift), a lower energy (red shift) or split into two levels. Two leading explanations are the Optical Stark Effect, in which the laser’s electric field directly modifies the exciton energy, and exciton-exciton interactions, in which excitons alter one another’s energies through many-body interactions.

In this work, the researchers used helicity-resolved transient absorption spectroscopy to show that, while the laser pulse is present, the Optical Stark Effect dominates, causing a blue shift, splitting or a red shift depending on the laser detuning. After the pulse ends, exciton-exciton interactions become dominant, producing a blue shift. By varying the laser detuning and tracking the exciton response on femtosecond timescales, the researchers were able to separate the coherent Optical Stark Effect from the later incoherent exciton-exciton interaction. The work provides a clearer picture of how light and excitons interact on ultrafast timescales, which is important for the design of next-generation optoelectronic devices.

Read the full article

A comprehensive multi-scale study on the growth mechanisms of magnetron sputtered coatings on open-cell 3D foams

Loris Chavée et al 2026 Prog. Energy 8 015002

Exciton band renormalization induced by optical Stark effect and exciton–exciton interaction in monolayer WSe2

Xiu Zhang et al 2026 Prog. Energy 8 025007

Do you want to learn more about this topic?

Advances in thermal conductivity for energy applications: a review Qiye Zheng et al. (2021)

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Intercalation in two-dimensional transition metal chalcogenides: interlayer engineering and applications by Dibyendu Ghosh, Pooja Devi and Praveen Kumar (2022)

The post Resolving an exciton debate appeared first on Physics World.

Laser processed thin NiO powder coating for durable anode-free batteries

Lorna Brigham — Mon, 26 Jan 2026 16:30:22 +0000

Traditional lithium‑ion batteries use a thick graphite anode, where lithium ions move in and out of the graphite during charging and discharging. In an anode‑free lithium metal battery, there is no anode material at the start, only a copper foil. During the first charge, lithium leaves the cathode and deposits onto the copper as pure lithium metal, effectively forming the anode. Removing the anode increases energy density dramatically by reducing weight, and it also simplifies and lowers the cost of manufacturing. Because of this, anode‑free batteries are considered to have major potential for next‑generation energy storage. However, a key challenge is that lithium deposits unevenly on bare copper, forming long needle‑like dendrites that can pierce the separator and cause short circuits. This uneven growth also leads to rapid capacity loss, so anode‑free batteries typically fail after only a few hundred cycles.

In this research, the scientists coated the copper foil with NiO powder and used a CO₂ laser (l = 10.6 mm) to rapidly heat the same in a rapid scanning mode to transform it. The laser‑treated NiO becomes porous and strongly adherent to the copper, helping lithium spread out more evenly. The process is fast, energy‑efficient, and can be done in air. As a result, lithium ions diffuse or move more easily across the surface, reducing dendrite formation. The exchange current density also doubled compared to bare copper, indicating better charge‑transfer behaviour. Overall, battery performance improved dramatically. The modified cells lasted 400 cycles at room temperature and 700 cycles at 40°C, compared with only 150 cycles for uncoated copper.

This simple, rapid, and scalable technique offers a powerful way to improve anode‑free lithium metal batteries, one of the most promising next‑generation battery technologies.

+ In an antiferromagnet, neighbouring spins prefer to align in opposite directions to minimise their energy. In a geometrically frustrated magnet, this is not always possible; for example, three spins on a triangle cannot all simultaneously be antiparallel to one another. The magnet PdCrO₂ contains chromium (Cr) atoms on a triangular lattice, so that the magnetic moments on the Cr atoms cannot point antiparallel to each other. This compound also contains sheets of palladium (Pd) atoms that have very high electrical conductivity. PdCrO₂ is therefore a system in which the interaction between magnetism and electronic structure can be studied in a precise way.

Previous studies have shown that the Cr-Cr exchange interaction is highly sensitive to inter-atomic spacing. In consequence, the magnetic ordering wavevector shifts rapidly as uniaxial stress is applied to PdCrO₂, distorting the triangular lattice. In this work, the researchers have taken a step further by applying enough stress to qualitatively change the magnetic structure. They use a combination of X-ray diffraction and measurement of the stress-strain relationship to probe the effects on the elastic properties, and elastic neutron scattering to see how the magnetism changes. As the magnetic structure changes, the Young’s modulus changes by around 100 GPa, showing that magnetic interactions have a large effect on the crystal’s mechanical stiffness.

As stress is initially applied to PdCrO₂, the magnetic wavevector changes rapidly, reflecting the sensitivity of the Cr-Cr exchange interaction to strain. The main finding of this work is that, under a uniaxial stress of about 0.6 GPa, the magnetism undergoes a first-order transition into a state where the magnetic wavevector is rigid, that is, no longer responds to continued change in lattice strain. The rigidity of this stress-induced magnetic structure is reflected in the elastic properties: the Young’s modulus almost doubles, and the Poisson ratio falls from about 0.7, an exceptionally high value, to about 0.3, which is more typical. This rigidity may be a consequence of nesting: the wavevector of this stress-induced magnetic phase nests the Fermi surface of the Pd sheets. PdCrO₂ may therefore provide a system in which the thermodynamics of nesting can be studied with quantitative precision. More broadly, the work demonstrates that uniaxial stress is a powerful tool for tuning frustrated magnetism and accessing new magnetic states.

Read the full article

Microgradient patterned NiO coating on copper current collector for anode-free lithium metal battery

Supriya Kadam et al 2025 Prog. Energy 7 045003

Uniaxial-stress-induced magnetic transitions in the triangular-lattice antiferromagnet PdCrO2

Nina Stilkerich et al 2026 Rep. Prog. Phys. 89 068007

Do you want to learn more about this topic?

Lithium aluminum alloy anodes in Li-ion rechargeable batteries: past developments, recent progress, and future prospects by Tianye Zheng and Steven T Boles (2023)

The post Laser processed thin NiO powder coating for durable anode-free batteries appeared first on Physics World.

Unusual ordered phases of highly frustrated magnets: a review by Oleg A Starykh (2015)

The post Tuning frustrated magnetism with stress appeared first on Physics World.

Planning a sustainable water future in the United States

Lorna Brigham — Mon, 26 Jan 2026 16:28:44 +0000

Within 45 years, water demand in the United States is predicted to double, while climate change is expected to worsen freshwater supplies, with 44% of the country already experiencing some form of drought. One way to expand water resources is desalination, where salt is removed from seawater or brackish groundwater to make clean, usable water. Brackish groundwater contains far less salt than seawater, making it much easier and cheaper to treat, and the United States has vast reserves of it in deep aquifers. The challenge is that desalination traditionally requires a lot of energy and produces a concentrated brine waste stream that is difficult and costly to dispose of. As a result, desalination currently provides only about 1% of the nation’s water supply, even though it is a major source of drinking water in regions such as the Middle East and North Africa.

Researchers Vasilis Fthenakis (left) and Zhuoran Zhang (right) from Columbia University taken at Nassau Point in Long Island (Courtesy: Zhuoran Zhang, Columbia University)

In this work, the researchers show how desalination of brackish groundwater can be made genuinely sustainable and economically viable for addressing the United States’ looming water shortages. A key part of the solution is zero‑liquid‑discharge, which avoids brine disposal by extracting more freshwater and recovering salts such as sodium, calcium, and magnesium for reuse. Crucially, the study demonstrates that when desalination is powered by low‑cost solar and wind energy, the overall process becomes far more affordable. By 2040, solar photovoltaics paired with optimised battery storage are projected to produce electricity at lower cost than the grid in the states facing the largest water deficits, making renewable‑powered desalination a competitive option.

The researchers also show that advanced technologies, such as high‑recovery reverse osmosis and crystallisation, can achieve zero‑liquid‑discharge without increasing costs, because the extra water and salt recovery offsets the expense of brine management. Their modelling indicates that a full renewable‑powered zero‑liquid‑discharge pathway can produce freshwater at an affordable cost, while reducing environmental impacts and avoiding brine disposal altogether. Taken together, this work outlines a realistic, sustainable pathway for large‑scale desalination in the United States, offering a credible strategy for securing future water supplies in increasingly water‑stressed regions.

Progress diagram adapted from article (Courtesy: Zhuoran Zhang, Columbia University)

+ https://physicsworld.com/?p=129309 + A new Quantum Monte Carlo method reveals distinct entanglement signatures of different quantum critical points

The post Probing quantum critical points appeared first on Physics World.

Could silicon become the bedrock of quantum computers?

Benyam Dejen — Mon, 26 Jan 2026 16:00:06 +0000

Silicon, in the form of semiconductors, integrated chips and transistors, is the bedrock of modern classical computers – so much so that it lends its name to technological hubs around the world, beginning with Silicon Valley in the US . For quantum computers, the bedrock is still unknown, but a new platform developed by researchers in Australia suggests that silicon could play a role here, too.

Dubbed the 14|15 platform due to its elemental constituents, it combines a crystalline silicon substrate with qubits made from phosphorus atoms . By relying on only two types of atoms, team co-leader Michelle Simmons says the device “avoids the interfaces and complexities that plague so many multi-material platforms” while enabling “high-quality qubits with lower noise, simplicity of design and device stability”.

Boarding at platform 14|15

Quantum computers take registers of qubits, which store quantum information, and apply basic operations to them sequentially to execute algorithms. One of the primary challenges they face is scalability – that is, sustaining reliable, or high-fidelity, operations on an increasing number of qubits. Many of today’s platforms use only a small number of qubits, for which operations can be individually tuned for optimal performance. However, as the amount of hardware, complexity and noise increases, this hands-on approach becomes debilitating.

Silicon quantum processors may offer a solution. Writing in Nature, Simmons, Ludwik Kranz, and their team at Silicon Quantum Computing (a spinout from the University of New South Wales in Sydney) describe a system that uses the nuclei of phosphorus atoms as its primary qubit. Each nucleus behaves a little like a bar magnet with an orientation (north/south or up/down) that represents a 0 or 1.

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These so-called spin qubits are particularly desirable because they exhibit relatively long coherence times, meaning information can be preserved for long enough to apply the numerous operations of an algorithm. Using monolithic, high-purity silicon as the substrate further benefits coherence since it reduces undesirable charge and magnetic noise arising from impurities and interfaces.

To make their quantum processor, the team deposited phosphorus atoms in small registers a few nanometres across. Within each register, the phosphorus nuclei do not interact enough to generate the entangled states required for a quantum computation. The team remedy this by loading each cluster of phosphorous atoms with a electron that is shared between the atoms. The result is that so-called hyperfine interactions, wherein each nuclear spin interacts with the electron like an interacting bar magnet, arise and provide the interaction necessary to entangle nuclear spins within each register.

By combining these interactions with control of individual nuclear spins, the researchers showed that they can generate Bell states (maximally entangled two-qubit states) between pairs of nuclei within a register with error rates as low as 0.5% – the lowest to date for semiconductor platforms.

Scaling through repulsion

The team’s next step was to connect multiple processors – a step that exponentially increases their combined capacity. To understand how, consider two quantum processors, one with n qubits and the other m qubits. Isolated from one another, they can collectively represent at most 2ⁿ+ 2^m states. Once they are entangled, however, they can represent 2ⁿ^{+ m} states.

Simmons says that silicon quantum processors offer an inherent advantage in scaling, too. Generating numerous registers on a single chip and using “naturally occurring” qubits, she notes, reduces their need for extraneous confinement gates and electronics as they scale.

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The researchers showcased these scaling capabilities by entangling a register of four phosphorus atoms with a register of five, separated by 13 nm. The entanglement of these registers is mediated by the electron-exchange interaction, a phenomenon arising from the combination of Pauli’s exclusion principle and Coulomb repulsion when electrons are confined in a small region. By leveraging this and all other interactions and control in their toolkit, the researchers generate entanglement of eight data qubits across the two registers.

Retaining such high-quality qubits and individual control of them despite their high density demonstrates the scaling potential of the platform. Future avenues of exploration include increasing the size of 2D arrays of registers to increase the number of qubits, but Simmons says the rest is “top secret”, adding “the world will know soon enough”.

The post Could silicon become the bedrock of quantum computers? appeared first on Physics World.

Is our embrace of AI naïve and could it lead to an environmental disaster?

No Author — Mon, 26 Jan 2026 11:00:38 +0000

According to today’s leading experts in artificial intelligence (AI), this new technology is a danger to civilization. A statement on AI risk published in 2023 by the US non-profit Center for AI Safety warned that mitigating the risk of extinction from AI must now be “a global priority”, comparing it to other societal-scale dangers such as pandemics and nuclear war. It was signed by more than 600 people, including the winner of the 2024 Nobel Prize for Physics and so-called “Godfather of AI” Geoffrey Hinton. In a speech at the Nobel banquet after being awarded the prize, Hinton noted that AI may be used “to create terrible new viruses and horrendous lethal weapons that decide by themselves who to kill or maim”.

Despite signing the letter, Sam Altman of OpenAI, the firm behind ChatGPT, has stated that the company’s explicit ambition is to create artificial general intelligence (AGI) within the next few years, to “win the AI-race”. AGI is predicted to surpass human cognitive capabilities for almost all tasks, but the real danger is if or when AGI is used to generate more powerful versions of itself. Sometimes called “superintelligence”, this would be impossible to control. Companies do not want any regulation of AI and their business model is for AGI to replace most employees at all levels. This is how firms are expected to benefit from AI, since wages are most companies’ biggest expense.

+ AI, to me, is not about saving the world, but about a handful of people wanting to make enormous amounts of money from it. No-one knows what internal mechanism makes even today’s AI work – just as one cannot find out what you think from how the neurons in your brain are firing. If we don’t even understand today’s AI models, how are we going to understand – and control – the more powerful models that already exist or are planned in the near future?

AI has some practical benefits but too often is put to mostly meaningless, sometimes downright harmful, uses such as cheating your way through school or creating disinformation and fake videos online. What’s more, an online search with the help of AI requires at least 10 times as much energy as a search without AI. It already uses 5% of all electricity in the US and by 2028 this figure is expected to be 15%, which will be over a quarter of all US households’ electricity consumption. AI data servers are more than 50% as carbon intensive as the rest of the US’s electricity supply.

Those energy needs are why some tech companies are building AI data centres – often under confidential, opaque agreements – very quickly for fear of losing market share. Indeed, the vast majority of those centres are powered by fossil-fuel energy sources – completely contrary to the Paris Agreement to limit global warming. We must wisely allocate Earth’s strictly limited resources, with what is wasted on AI instead going towards vital things.

To solve the climate crisis, there is definitely no need for AI. All the solutions have already been known for decades: phasing out fossil fuels, reversing deforestation, reducing energy and resource consumption, regulating global trade, reforming the economic system away from its dependence on growth. The problem is that the solutions are not implemented because of short-term selfish profiteering, which AI only exacerbates.

Playing with fire

AI, like all other technologies, is not a magic wand and, as Hinton says, potentially has many negative consequences. It is not, as the enthusiasts seem to think, a magical free resource that provides output without input (and waste). I believe we must rethink our naïve, uncritical, overly fast, total embrace of AI. Universities are known for wise reflection, but worryingly they seem to be hurrying to jump on the AI bandwagon. The problem is that the bandwagon may be going in the wrong direction or crash and burn entirely.

Why then should universities and organizations send their precious money to greedy, reckless and almost totalitarian tech billionaires? If we are going to use AI, shouldn’t we create our own AI tools that we can hopefully control better? Today, more money and power is transferred to a few AI companies that transcend national borders, which is also a threat to democracy. Democracy only works if citizens are well educated, committed, knowledgeable and have influence.

AI is like using a hammer to crack a nut. Sometimes a hammer may be needed but most of the time it is not and is instead downright harmful. Happy-go-lucky people at universities, companies and throughout society are playing with fire without knowing about the true consequences now, let alone in 10 years’ time. Our mapped-out path towards AGI is like a zebra on the savannah creating an artificial lion that begins to self-replicate, becoming bigger, stronger, more dangerous and more unpredictable with each generation.

Wise reflection today on our relationship with AI is more important than ever.

The post Is our embrace of AI naïve and could it lead to an environmental disaster? appeared first on Physics World.

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How did you do?

0–4 Back to stage school

5–9 Wooden performance

10–13 Leading light

14 Darling, you were wonderful

Feeling stuck? Check out the feature “Theatre is bringing physics to new audiences but what is the definitive science play?” by Chris Sinclair

The post Take this quiz to test your knowledge of science on stage appeared first on Physics World.

NASA launches Nancy Grace Roman Space Telescope to shed light on the dark universe

Peter Gwynne — Tue, 01 Sep 2026 12:43:17 +0000

NASA has successfully launched the $4.3bn Nancy Grace Roman Space Telescope. The observatory took off atop a SpaceX Falcon Heavy rocket from Florida’s Kennedy Space Center at 7:26 a.m. local time on 30 August. The craft will now spend three months travelling to a point in space known as the second Sun–Earth Lagrange point (L₂) where it will survey space with a field of view at least 100 times greater than the Hubble Space Telescope.

From L₂, which lies about 1.6 million kilometres from Earth, the Nancy Grace Roman Space Telescope will yield insights into dark energy and dark matter, discover and characterize exoplanets, map billions of galaxies, and gain fresh understanding of black holes.

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It will do so via a 2.4-m primary mirror that is accompanied by two instruments: a wide-field instrument will obtain images in visible and near-infrared light while an experimental coronagraph will use masks, prisms and mirrors to cancel out the light from stars to help detect exoplanets.

“Roman will be a discovery machine that will bring us closer than ever before to answering humanity’s most profound questions about our cosmic history,” notes Nicola Fox, associate director for NASA’s Science Mission Directorate.

NASA intends the observatory to operate for at least a decade with three specific surveys planned for its initial five years. The first will identify tens of thousands of distant supernovae, many more than the 2000 currently known, while a second survey will observe more than a billion galaxies.

Both these sets of measurements, combined with data from other survey telescopes, will be used to improve our understanding of dark energy and its potential role in the speed at which the universe expands. Their observations of gravitational lensing will also allow astronomers to map dark matter.

A third survey, meanwhile, will search the centre of the Milky Way for signs of gravitational microlensing that will reveal more than 2000 otherwise invisible exoplanets.

Space surveyor: the observatory will yield insights into dark energy and dark matter, study exoplanets, map billions of galaxies and to gain fresh understanding of black holes. (Courtesy: SpaceX)

Mother Hubble

The observatory was initially known as the Wide-Field Infrared Survey Telescope before it underwent several design changes due to cost pressures. In 2020 it was then renamed after Nancy Grace Roman (1925–2018), who in the early 1960s became NASA’s first chief astronomer and is known as “the mother of the Hubble Space Telescope”.

Yet the Roman observatory won’t replace Hubble or the James Webb Space Telescope, rather it will complement them, providing data from wide areas of the universe that those two instruments will then be able to observe in greater detail.

Indeed, Roman will survey the universe one thousand times faster than the Hubble, creating 1.4 billion terabytes (1.4 zettabytes) of information daily – the highest data rate of any NASA astrophysics mission.

NASA says that machine learning, artificial intelligence and “citizen science” will be used to help sift through the data and flag findings that astronomers will then study.

NASA administrator Jared Isaacman praised the mission as “exactly the kind of success story we want to see”. He noted that it was completed “ahead of schedule and on budget”, adding that it “will demonstrate what is possible when America’s space programme pairs bold ambition with disciplined execution”.

The post NASA launches Nancy Grace Roman Space Telescope to shed light on the dark universe appeared first on Physics World.

New sensor uses topological material to detect helium leaks

Isabelle Dumé — Mon, 26 Jan 2026 09:00:06 +0000

As audiences poured out of London’s Old Vic theatre on a crisp night in January, one theatregoer and their companion were overheard chatting about the second law of thermodynamics. “I wish I knew more about what they were discussing,” one remarked, referring to the characters in Tom Stoppard’s Arcadia. “It’s an unusual play,” the other responded.

Was this curiosity about thermodynamics a sign of confusion, that the production had failed to communicate its ideas clearly for a lay audience? Or had the evening in the theatre inspired a desire for these audience members to dig deeper and learn more about physics through the shared experience of watching a play?

Written in 1993, Arcadia is an early example of an ever-growing number of plays that have at their heart scientific ideas or scientists themselves. Newtonian determinism, chaos and iterated algorithms all crop up in Stoppard’s masterpiece, but Arcadia is a play about much more than just physics or mathematics.

With scenes alternating between a country house in the early 19th century and the present day, Arcadia is also a literary mystery about the poetry of Byron set against academic rivalry. Like all of Stoppard’s work, it’s an agile, clever and entertaining tour de force of ideas, led by characters who are just as concerned with traditional dramatic themes including love, jealousy and flawed ambition.

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The Old Vic’s Arcadia was sufficiently popular with audiences that it received a transfer to London’s West End for an extended run in summer 2026. But it was not the only major revival of a classic “science play” in London this year, with Hampstead Theatre staging a new production of Michael Frayn’s Copenhagen.

Arguably no other play about physics has been as popular and successful as Copenhagen since it was first produced at the National Theatre in London 1998. It imagines what might have been discussed when Werner Heisenberg visited Niels Bohr at his home in the Danish capital during the Second World War. It also explores the implications of the meeting for the development of nuclear weapons.

Plays depicting physics or physicists fall into three main types. Some are straightforward biographical representations of physicists – from Lise Meitner to Stephen Hawking. Others focus on the process of “doing” physics. A third kind uses scientific concepts to structure the play itself. Copenhagen is perhaps unique in achieving all these feats at once.

Curtains up

The representation of scientists on stage is not a new phenomenon. The ambitious alchemist and natural philosopher Doctor Faustus, who sold his soul to the devil in Christopher Marlowe’s 16th-century play of the same name, is one early example of a learned character who could be considered a scientist seeking worldly knowledge at a cost.

Strange encounter The Devil and Doctor Faustus Meet is an 1825 illustration of the play Doctor Faustus by Christopher Marlowe, which was one of the earliest stage shows to feature scientific ideas. (Source: Wellcome Collection)

Later, in 1823, there was a highly popular stage adaption of Mary Shelley’s novel Frankenstein. Performed at the English Opera House in London, Presumption; or, the Fate of Frankenstein by Richard Brinsley Peake was what first brought Shelley’s book to public prominence, reigniting suspicions of the motivations of scientists as a potential force for good or evil.

While Frankenstein led the way in the genre of science fiction, which I will not cover here, the notion of the “physics play”, where physics or physicists feature deeply, can be more readily traced to the 20th century. Bertolt Brecht’s A Life of Galileo, written in 1938, is perhaps one of the first clear examples to represent the life and work of a real scientist on stage.

First performed in German in Zurich in 1943, A Life of Galileo presents the audience with an account of a scientist whose life is well documented in the historical record. It depicts scenes from Galileo’s life including his prosecution for heresy by the church for promoting the heliocentric universe.

Astronomy in action Dava Sobel’s play And the Sun Stood Still was produced in 2014 by Boulder Ensemble Theatre Company, starring Benjamin Bonenfant (left) as mathematician Georg Rheticus and Jim Hunt (right) as Nicolaus Copernicus. (Photograph by Michael Ensminger. Used with permission)

Since then we’ve seen plenty of other plays about real-life physicists. Also dealing with the heliocentric solar system is acclaimed science writer Dava Sobel’s short 2011 play And the Sun Stood Still (first published in her book A More Perfect Heaven). It concerns an episode in the life of Nicolaus Copernicus, depicting his discussions with mathematician Georg Rheticus when he visited Poland in 1539.

The period of scientific advancement that followed in the 17th century is represented in a number of plays depicting the life of Isaac Newton. A notable example is Craig Baxter’s Let Newton Be!, a verbatim play based on Newton’s own words that was written to celebrate the University of Cambridge’s 800th anniversary in 2009.

It was performed by Menagerie Theatre Company for the first time in 2009 at Trinity College, Cambridge, where Newton had once been a fellow. Three actors simultaneously portray Newton at different points in his life, from boyhood to establishment figure, continually interacting with each other on stage. Baxter aims to give a less conventional perspective on Newton’s life than the usual image of a scientist beneath an apple tree.

Historical heroes Left: Let Newton Be! by Craig Baxter was toured from 2009 to 2011 by Menagerie Theatre Company with a cast that included David Meyer as Isaac Newton in later life. (Courtesy: Menagerie Theatre Company/Jaimie Gramston). Right: Siobhán Nicholas’ play Hanging Hooke, toured by Take the Space from 2008 onwards, starred Chris Barnes as Newton’s scientific rival Robert Hooke. (Photographer Ken Goodson, copyright Take the Space Theatre Company Ltd)

Newton’s contemporary and arch enemy Robert Hooke was also memorably represented by the actor Chris Barnes in Siobhán Nicholas’ 2008 one-man play Hanging Hooke. It was toured by Take the Space theatre company, which Barnes co-founded, to venues across the UK, including a performance at the Royal Society itself.

In a follow-up to Hanging Hooke, Take the Space also represented the contributions to astronomy of Caroline Herschel in the 18th and 19th centuries. Her work, which is arguably less well known than that of her brother William Herschel, appeared in STELLA: a Story of Women, Their Men and Astronomy, also written by Nicholas.

Centre stage

Some episodes in the history of physics are more thoroughly documented then others, lending rich source material for drama. Such is the case in Katherine Moar’s play Farm Hall about the German physicists who were famously held captive in a country house in Cambridgeshire, UK, at the end of the Second World War.

The play features six characters, all of them real scientists, including Heisenberg, Kurt Diebner and the pioneering radiochemist Otto Hahn. Their words were secretly recorded by their British military captors in 1945 in an attempt to find out how close, if at all, the German scientists were to developing a nuclear bomb.

Ethical matter Physicists’ involvement in nuclear weapons has been a rich source of material on the stage, including this 2023 production of Farm Hall by Katherine Moar, at the Jermyn Street Theatre in London. It included Archie Backhouse (left) as Erich Bagge, Forbes Masson (centre) as Otto Hahn and Alan Cox (right) as Werner Heisenberg, who were among six German physicists held captive by the British military after the Second World War to uncover their role, if any, in Germany’s attempt to build nuclear weapons. (Photograph by Alex Brenner. Used with permission)

Moar’s play is one of several that use the Farm Hall transcripts as the basis of a play text, another being Operation Epsilon by US playwright Alan Brody. Originally written in 2013, it received its British premier at the Southwark Playhouse in London in 2023, and examines the ethics of those involved in nuclear weapons programmes.

That theme was also tackled in Christopher Nolan’s blockbuster movie Oppenheimer, which was one of the biggest film successes of recent years. However, J Robert Oppenheimer has been represented on stage too, not least in Tom Morton-Smith’s 2015 play Oppenheimer, in which key figures in the Manhattan nuclear-bomb project were re-enacted in a large-scale production at the Royal Shakespeare Company (RSC).

Morton-Smith’s play aimed to capture the scale and scope of a so-called Shakespearean “history play”, with a significant but flawed character at its heart, although this is arguably a tough feat to achieve. In fact, Oppenheimer played at the RSC in Stratford-upon-Avon simultaneously with Hamlet.

Dramatis personae

In each of the examples above, the physicists portrayed are real people, whose names and work will be familiar from textbooks and the historical record. Other physicists to have been the subject of plays include Jocelyn Bell Burnell, Ludwig Boltzman and Wolfgang Pauli, while Nicole Kidman played DNA-structure pioneer Rosalind Franklin in Anna Ziegler’s Photograph 51.

Physicists as fictional characters and the act of doing physics are also increasingly being represented on stage, with collaboration in big-science projects becoming central
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However, physicists as fictional characters and the act of doing physics are also increasingly being represented on stage, with collaboration in big-science projects becoming central. Especially fruitful as source material have been activities at CERN and particularly the Large Hadron Collider (LHC), which gained growing public awareness during the hunt for the Higgs boson in the first two decades of the 21st century.

Playwright Lucy Kirkwood had already published a play with nuclear scientists as characters in The Children in 2016 (currently playing at Lyric Hammersmith). But it was her play Mosquitoes, produced at the National Theatre in 2017, that centred on scientific themes. Many scenes are set at the LHC and its central character, Alice, is a research physicist based in Geneva who has a complex relationship with her sister, Jenny.

Colliding characters Mosquitoes by Lucy Kirkwood, performed at the National Theatre in 2017, starred Olivia Williams (right) as a physicist working at CERN, and Olivia Colman (left) as her sister. (Courtesy: Brinkhoff & Mogenburg)

The play’s depiction of the two sisters centralizes the process of collaboration that is key to large-scale science research. Olivia Colman and Olivia Williams played the main characters in Mosquitoes in the National Theatre production, which benefited from some funding from the Institute of Physics, which publishes Physics World.

On a smaller scale to Mosquitoes, but also set in the periphery of CERN, is Morton-Smith’s one act play The Earthworks. Set on the eve of the switch on of the LHC, it features two strangers – a journalist and a physicist – who meet in a hotel bar in Geneva and talk about their loves and fears.

The anticipation and magnitude of the imminent new experiment gives the two characters cause to reevaluate their own lives and relationships. Although not widely produced, The Earthworks is an engaging short drama that again normalizes the process of big science in the wider cultural context through theatre.

Structured text

Featuring a physicist as a main character is also key to Constellations by Nick Payne, a playwright who has often included scientific ideas in his work. First performed in 2012 at the Royal Court Theatre, it features a physicist and beekeeper who meet at a picnic and begin a series of scenes replayed over and over again.

Unlike straightforward biographical-style plays, Constellations is a great example of a play that uses a scientific principle as a metaphorical device to help shape the play itself. Its structure is essentially inspired by the “multiverse” interpretation of physics, which implies there may be a potentially infinite number of copies of ourselves in different worlds.

The many iterations of similar scenes in Constellations make it a challenging production for actors – although not necessarily for audiences, provided the acting is good. And having only two characters on stage proved handy during the COVID-19 pandemic, when strict social-distancing rules meant it was helpful to have such a small cast.

In fact, when Constellations was revived in 2021 at the Vaudeville Theatre in London, different pairs of celebrity actors were used in different performances. Pairings included Peter Capaldi with Zoë Wanamaker, and Omari Douglas with Russell Tovey.

Two’s company Constellations by Nick Payne is a two-hander with multiverse themes. In 2021 it was produced at the Vaudeville Theatre with several different casts. Clockwise from top left: Chris O’Dowd and Anna Maxwell Martin; Peter Capaldi and Zoë Wanamaker; Omari Douglas and Russell Tovey; Sheila Atim and Ivanno Jeremiah. (Photographs by Marc Brenner. Used with permission)

“I loved staging Constellations,” says the theatre director Michael Longhurst, who originally worked with Payne on the play. “When a writer does that work to understand the science for us lay audience members and then puts them into a human context in a dramatic setting, then I think there is a real gift.”

Incorporating physics into the structure of a play has also been tackled more than once by Tom Stoppard, who died last year. In Hapgood, his attempt at a spy thriller, quantum physics plays a role in structuring the play by experimenting with quantum uncertainty as a plot device. First performed in 1988, the complexity of the plot proved confusing for audiences and, although revived subsequently, it was one of Stoppard’s less successful plays.

The bewildering twists and turns of Hapgood are in strong contrast to Arcadia, which has proved a far more popular science-themed play from the great playwright. It toys with ideas of determinism and iterated algorithms in a rich drama.

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Like many Stoppard plays, audiences appreciate the playfulness of ideas but can at times feel alienated by the complexity of the discourse. Nonetheless, Arcadia is a hugely significant play when it comes to science in theatre and its recent success at the Old Vic and subsequent West End transfer over 33 years later is evidence of its endurance.

It’s worth noting, however, the existence of several plays that appear to have a strong physics connection – but in fact have very little at all. Notable examples include Friedrich Dürrenmatt’s 1962 play The Physicists (which was more of a satire) and Simon Stephens’ 2015 play Heisenberg: the Uncertainty Principle. Stephens was perhaps capitalizing on a growing public awareness of “uncertainty”.

Copenhagen: the definitive physics play

Conversely, you could be forgiven for thinking that a play called Copenhagen would be largely about the Danish city. But Frayn’s drama is one of the most significant examples of a play about and featuring physicists. With just three actors on stage and minimal set or plot, it is perhaps a surprise that Copenhagen could capture the attention of theatre goers for over two hours.

However, the text is a richly researched and thought-provoking drama that successfully achieves several things at once. First, it is a faithful account of the lives and work of Bohr and Heisenberg, insofar as we can know these two Nobel-prize-winning physicists, provoking historically meaningful questions.

Second, it gives an audience a sense of the excitement, frustration and invigoration of the act of doing science through the reminiscences and insights of its characters reflecting on the heyday of the development of quantum theory.

Stars of the stage Michael Frayn’s Copenhagen, which is perhaps the archetypal physics play, was revived in 2026 at Hampstead Theatre. It starred Richard Schiff (left) as Niels Bohr, Damion Molony (centre) as Werner Heisenberg and Alex Kingston as Margrethe Bohr. (Photograph by Marc Brenner. Used with permission)

Third, it successfully embeds concepts of uncertainty and complementarity within the text and structure of the play itself – in a way that other writers have fallen short of achieving. Copenhagen perhaps stands out among all other plays that deal with physics as achieving all three of these things at once, accounting for some of its enduring appeal, not least to physicists.

In a conversation with Physics World earlier this year, Frayn admitted that physicists hadn’t held back in pointing out mistakes. “Some of the physicists who have seen Copenhagen have taken the trouble to write to me and to point out errors I had made in the science, in spite of all my efforts,” he says. “I have as a result made a number of corrections in succeeding productions over the years. I am very grateful to them.”

Copenhagen tackles the historical and moral dimensions of nuclear weapons in a way that is as relevant today as when it was written
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The care with which Frayn researched and adapted Copenhagen enables it to tackle the historical and moral dimensions of the development of nuclear weapons in a way that has made it as relevant today as when it was written. The production at Hampstead Theatre in spring 2026 was the latest in a long line of revivals of the play around the world since its first critical and popular success in 1998. In addition to Howard Davies’ 2002 film version, Emma Harding adapted Copenhagen for radio in 2013, featuring Simon Russell Beale, Benedict Cumberbatch and Greta Scacchi.

Curtains down

So were the Old Vic theatregoers wandering down the street after seeing Arcadia enthused or confused by their encounter with thermodynamics in the theatre? Should we celebrate or be sceptical of plays that put physics at their core? There is arguably no reason why physics should have a place in theatre any more or less than any other aspect of human endeavour.

However, as the importance of science becomes more embedded as an essential part of our culture in general, the role for physics in the theatre continues to grow. Current writers such as Moar and Kirkwood will continue to build on the achievements of the old guard such as Frayn and Stoppard, whether that be representing the history of physics, portraying physicists as characters or using science within the structure of a play.

In the rarest of cases all three can be achieved at once and it is intriguing to wonder how long it will be until another play comes along to match the might of Copenhagen as the definitive physics play.

What do you think? What makes a good physics play and what’s your favourite production? Let us know by e-mailing pwld@ioppublishing.org

The post Theatre is bringing physics to new audiences but what is the definitive science play? appeared first on Physics World.

Sliding water droplets corrode Teflon-coated metal

Tim Wogan — Tue, 01 Sep 2026 07:19:50 +0000

Water droplets sliding across solid surfaces can acquire electric potentials of thousands of volts and thereby corrode non-conductive surfaces on metals when they discharge. That is the conclusion of researchers in Germany who say that the poorly-understood phenomenon warrants further investigation to help prevent corrosion of vulnerable outdoor equipment and cultural heritage sites.

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Metal corrosion by water droplets is a serious economic and safety issue, and prevention begins with the proper understanding of the relevant processes. Conventional wisdom is that most corrosion is caused by a combination of physical abrasion by the motion of the droplets and chemical degradation from natural acids and anthropogenic pollutants in the water. The notion that electrochemistry might play a significant role in corrosion had not been seriously considered, says physical chemist Hans-Jürgen Butt of the Max Planck Institute for Polymer Research in Mainz.

Part of the reason, he believes, is that, until relatively recently, it was thought that the triboelectric effect (electrically charging objects by rubbing them together) did not work in liquids. “If you have a solid and you rub another insulating solid against it you get electron transfer – I think this has been known for more than 2500 years” he says. However, this relies on atomic-scale roughness of the surface to concentrate charge at specific points where bonds can be broken – and fluids cannot, by definition, be rough.

“If you take a water droplet and let it slide there is some mechanical force from surface tension, but that’s much too low,” says Butt. “There is no way you could generate enough energy locally to pick up an electron or to put an electron or an ion from the water onto the surface.” In the past 10 years, however, it has become increasingly clear that sliding droplets do become highly charged.

Sloping surfaces

In their present work Butt and colleagues deposited water droplets onto copper surfaces covered with 60 nm of Teflon. When they dropped droplets straight onto the surface, they observed no corrosion. They then deposited droplets first onto a variety of other sloped insulating surfaces such as plant leaves, PVC construction boards and the perfluorooctadecyltrichlorosilane (PFOTS) hydrophobic coating often used on window glass. The droplets ran down these surfaces and then fell onto the Teflon-coated copper. After around 3000 droplet impacts, atomic force microscopy and confocal microscopy revealed evidence that the droplets had corroded both the coating and the underlying copper.

The researchers believe that the droplets become positively charged as they slide down the sloping surface. As they fall onto the coating, the potential difference between the copper and the underlying copper can exceed 1 kV. This is greater than the dielectric breakdown strength of the coating, causing the droplet to discharge. This damages the coating and leaves the underlying metal vulnerable to further oxidation.

To test their hypothesis, the researchers measured charge movement within the copper surface, showing that negative charge flowed towards droplets dripping off insulating surfaces. They also used high-speed cameras to show that, whereas a drop deposited directly retained its spherical shape before impact, a dripping drop was drawn into a cone shape, producing a tip of positive charge that would increase its corrosive capacity.

Uncertain consequences

The practical implications of this are unclear. “Technical coatings on cars, ships etc. are typically 100 microns and thicker, so the process we describe is probably not of direct relevance,”says Butt. However, the phenomenon could be involved in the degradation of monuments and other outdoor historical objects. “We have evidence that surfaces change their properties when you slide charges over them, but the real consequences are not yet known,” explains Butt.

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He says his own group is most clearly focused on understanding the fundamental physics involved. “We still don’t know why the heck there is such a charge separation: it’s energetically unfavourable, it should not happen, but it happens.” he says. “The one effect we describe here is, in a way, pretty trivial – everyone knows that if you have a high potential and it’s somehow grounded there is a breakthrough – but what happens at the surface with this deposited charge is not clear.”

Materials scientist Zhong Lin Wang of Georgia Institute of Technology in Atlanta was one of the first researchers to discover the triboelectric effect in liquids, and helped to develop the triboelectric nanogenerator used to quantify it. “The transferred electrons can be kicked back to the water solution, resulting in chemical reaction at the vicinity surface. This process, called contact-electro-catalysis, was first proposed in 2022, and is now an active field of research in chemistry, materials and environmental science.” He says. “[Butt and colleagues] show that the electrons transferred from the water droplet can ‘break’ the surface coating layer and lead to local oxidation. This is an interesting discovery.”

The research is described in Nature.

The post Sliding water droplets corrode Teflon-coated metal appeared first on Physics World.

Encrypted qubits can be cloned and stored in multiple locations

No Author — Sat, 24 Jan 2026 15:09:46 +0000

Dose calculations Left: dose distributions for thoracic pMBRT without motion (3D), with respiratory motion (4D) and with respiratory motion at high dose rate (4D HDR). Right: dose distributions for a brain treatment with zero shift, a 1 mm shift and a 2 mm shift. (Courtesy: Phys. Med. Biol. 10.1088/1361-6560/ae8ef8)

Proton minibeam radiotherapy (pMBRT) is an innovative new cancer treatment that uses an array of narrow proton beams to create alternating regions of high and low dose, before converging to a homogeneous dose distribution within the target volume. Numerous studies in small animals have shown that this spatially modulated dose distribution can destroy tumours while sparing healthy tissue and reducing side effects.

To implement pMBRT in the clinic, it’s important to first assess the impact of organ motion during treatment, which could lead to overlapping of the dose peaks and valleys, and potentially diminish the sparing effect. With this aim, a team at Institut Curie in France has developed a Monte Carlo (MC)-based framework to quantify the dose distribution for realistic clinical treatments, reporting their findings in Physics in Medicine & Biology.

To deliver pMBRT, a multi-slit collimator is used to create narrow beams, typically 0.3 to 1 mm wide, spaced 2 to 6 mm apart. As this collimator blocks much of the initial proton beam, longer treatments are needed to deliver the prescribed dose, increasing the likelihood of organ motion.

“Given the longer irradiation times, possible patient movement could deteriorate the heterogeneous spatial dose distribution of pMBRT,” explains senior author Ludovic De Marzi. “This is all the more problematic because it is this heterogeneous distribution that is believed to be responsible for the technique’s biological sparing effect.”

The dose reconstruction workflow

De Marzi and colleagues developed a 4D dose calculation workflow based on time-resolved MC simulations to determine how motion affects pMBRT dose distribution. The tool requires two main inputs: a 4D CT dataset capturing the patient’s anatomy and breathing motion over one respiratory cycle; and a proton pencil-beam scanning (PBS) treatment plan created on a reference CT.

To validate their workflow, the researchers irradiated a thoracic motion phantom with a conventional PBS plan and compared the measured dose with the simulations. For a 3%/3 mm gamma index (a standard quality check tool), the mean pass rate for nine phantom irradiations was 97.3%, confirming that the calculation performs reasonably well for 4D dose modelling in conventional PBS.

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They then used the tool to assess the impact of motion in representative clinical cases, first examining a thoracic treatment with large breathing movements. They calculated 4D dose distributions for three scenarios: 3D pMBRT without motion; 4D pMBRT with 20 mm breathing motion; and 4D high-dose rate pMBRT, with the instantaneous dose rate increased tenfold to reduce beam-on time by a factor of ten.

The calculated dose distributions showed that breathing motion introduced significant variations in the patterns of peaks and valleys, impacting a crucial parameter: the peak-to-valley dose ratio (PVDR). At a depth of 5 mm, for example, the mean PVDR dropped from 11.9 for the 3D scenario to 6.7 in 4D. The high-dose rate scheme slightly mitigated this degradation, but not significantly.

“The PVDR is an index that takes into account both doses in the valleys (which are likely correlated with the biological sparing effect on healthy tissue) and the maximum delivered doses (which are likely responsible for the anti-tumour effect),” De Marzi explains. “It can also be used to help optimize the 3D dose distribution of the treatment plan.”

Breathing motion also degraded the dose delivered to the tumour, with the mean target dose and D_95% (the minimum dose received by 95% of the target volume) reduced by 30% and 35%, respectively, for 4D pMBRT. Nearby organs-at-risk (OARs) were also impacted, with a decrease in dose to the stomach and a significant increase in mean dose to the spleen for the 4D cases.

The researchers next examined an intracranial treatment. While there is no intra-organ motion in this case, the patient’s head undergoes small rigid translations – generally limited to less than 1 mm using thermoplastic masks. As such, they modelled patient motion as a simple continuous 1 or 2 mm translation.

Motion did not significantly impact the mean dose or D_95%for the target or OARs. A 1 mm shift was, however, enough to degrade the peak–valley patterns, reducing the mean PVDR by 10% from the static case (at 15 mm depth). For a 2 mm shift, this increased to a 24% reduction in mean PVDR.

A valuable tool

The researchers conclude that their 4D dose reconstruction workflow provides a useful tool for assessing interplay effects caused by organ motion during pMBRT. Without a specific motion management strategy, only intracranial treatment with movements below 1 mm was robust to interplay effects. A similar workflow could prove valuable for estimating the sparing effect of pMBRT while accounting for patient motion and adapting treatment plans accordingly.

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Looking forward, it may be possible to minimize delivery times by combining pMBRT with the ultrahigh-dose rate delivery used for FLASH treatments.

“This idea is appealing because it could both solve the problem of reduced dose rate in pMBRT and add an additional biological effect (FLASH) to further spare healthy tissue,” says De Marzi. “However, its feasibility remains to be demonstrated, as does the value of developing a technique that combines such considerable complexities. A simple increase in dose rate – without going as far as FLASH – would already be of interest.”

In their next step towards clinical application, De Marzi and colleagues are working to validate calculation tools and measurement procedures tailored to this pMBRT technique. “Ones that are fast, accurate and usable by clinicians,” he says.

The post Dose calculations reveal how patient motion impacts proton minibeam therapy appeared first on Physics World.

Cosmic time capsules: the search for pristine comets

James Dacey — Fri, 23 Jan 2026 13:40:59 +0000

Whether it’s cosmology, quantum mechanics or particle theory, most of us go into physics because we’re fascinated by the universe and its mysteries – and not because of the career options it might lead to. In fact, by the time you’re at university, you’re so snowed under with lectures, labs, coursework and tutorials – not to mention having fun – that there’s almost no time to think about what to do after graduating.

It doesn’t help either that most university staff are only familiar with careers in research, and so aren’t the best career mentors for physics students exploring the many options outside academia. That’s why Physics World has published countless careers articles over the years looking at what physicists do after they graduate – not just in research but also in industry, finance, teaching, IT and engineering. Each year we also gather many of these into our annual Physics World Careers guide – which includes a directory of employers seeking physics graduates.

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But when the time comes to look for a job or plan your next steps, you won’t want to plough through every guide we’ve published. So to help you through the maze of options, this article brings together all our tips, information and help in one place. In today’s tough job market, a physics degree is an absolutely fantastic thing to have, giving you a deep technical knowledge and an ability to think rigorously. But before even starting to apply for jobs or courses, you first need to sit down and think hard about what it is that makes you happy and fulfilled in life.

Stop and think

As Crystal Bailey from the American Physical Society advised in a 2025 Physics World Live discussion “Not sure what to do with your physics degree? Our expert panel give their careers advice”, first ask yourself what it is you want for your career and your life. Do you prefer theoretical questions or practical problems? Do you like working alone or with people? Do you want a good work–life balance, a flexible schedule or just to make pots of money? “You need to understand what will be a good match for you,” she advises.

We suggest you do this kind of self-reflection long before you expect to graduate – don’t leave it to the last minute when you’re short of time. It also helps to make an audit of all the “soft skills” you have as a physicist, of which there are 16 different kinds. From being able to manage your time, knowing how to communicate or sort out conflict, these attributes are just as important to employers as your technical prowess.

Think for a minute Before even starting to apply for jobs, first reflect on what it is you want from life. (Courtesy: iStock/Layla Bird)

The “hard” skills you gained while studying – such as knowing how to solve a differential equation or line up mirrors on an optics bench – are easy to provide evidence for, from the modules you took, or the lab work you did. But the other more nuanced and practical skills – such as presenting in front of your peers, writing reports or keeping to deadlines – are just as crucial.

While you’re still at university, it also helps to take advantage of the huge amount of talented people you’re surrounded by – or as Katie Perry, a physicist who works at the Daphne Jackson Trust, once put it, “network like crazy”. Scientific meetings, talks and conferences are a great place to do this, where our tip is to devise an “elevator pitch” – a short and pithy statement of who you are. If someone asks you about yourself, you can then confidently reel off a few well-considered words.

Networking doesn’t necessarily come easy so if you find it awkward, you just need to get out there and practise. As science communicator Claire Malone believes, networking doesn’t have to be scary and something that only super confident people excel at. Learn to ask questions, be a good listener, take an interest in other people – and remember to ask for their business card so you can contact them later.

And our final piece of advice before even brushing up your CV or creating a LinkedIn page is to get a sense of the current job market for physics. It always goes through ups and downs, with the rise of artificial intelligence (AI) causing huge uncertainty right now. But overall there are some constant characteristics to the physics jobs market, as you can find out in a 2023 Institute of Physics report, which is packed with information about the UK physics jobs market by size, location and salary.

From reflection to action

So now you’ve done all that self-reflection, analysed the job market, audited your soft skills, and had a go at networking, it’s time to start applying for things to do after you graduate.

A number of you might be considering a PhD and, if so, we have some specific advice just for you (see “The PhD pathway” box below). But more than half of today’s graduates move into the private sector and pursue industry careers instead. If that’s your target, plan ahead by spending a summer interning at a company and try to find the right mentor for you. It’s also a good idea to do some extracurricular activities beyond your core academic aims, which will help you develop a range of transferable skills that can help you switch into a different area beyond physics.

The PhD pathway

(Courtesy: iStock/elenabs)

For graduates who choose to remain in academia, and have found a PhD position, resilience and critical thinking are key skills to have. While it can be exciting and fulfilling to do your own research for the first time, completing a PhD is challenging. Most people have tough moments during a PhD, but people don’t often share their difficulties and it’s easy to think you’re the only one struggling.

Creativity is the backbone of scientific success so, if you’re doing a PhD, take the time to have a break and let new ideas come to light. Things can go wrong – from funding cuts to global pandemics – and it’s important to make sure that you value your mental health and don’t burn out. If you are one of the many neurodivergent people in science, it’s a good idea to ensure you have the accommodations necessary for success, and to embrace your diversity and the unique perspective you bring to your work.

Once you have completed all your research and gathered your data, the final step is to write your thesis – which can be a particularly stressful task, so its important to find different ways to motivate yourself and complete that final hurdle. Even if you don’t stay in academia, a PhD will teach you a lot about how to get ahead under your own steam and complete a major piece of work on your own.

From interstellar wanderers to carefully orchestrated intercepts, this episode blends pioneering missions and cosmic detective work. Keep up to date with all the latest space and astronomy developments in the dedicated section of the Physics World website.

A degree in physics opens doors into many different fields, from nuclear energy to quantum and beyond (see “Across the physics careers spectrum” box below). You might also be keen to use your physics skills in a more lateral way, whether in scientific patent law or science communication. You may choose to be an entrepreneur and set up your own business or decide to teach future generations of physicists. Remember, if your original plan doesn’t pan out as you imagined, it’s never too late to take a risk and make a change even at a later stage of your career.

Across the physics careers spectrum

Take your pick From medical physics to green energy, and everything in between; your physics degree offers you many options. (Top row: Shutterstock/hrui; iStock/peshkov; Shutterstock/shaneinsweden. Bottom row: Shutterstock/Yevhen Vitte; iStock/chayanan; iStock/Peter Hermes Furian)

Green energy and sustainability: Physics graduates are ideally placed to tackle the world’s environmental challenges, with their technical knowledge and problem-solving skills. You can find out more about the physicists who are doing their bit to build a greener, more sustainable future in the field of decarbonizing energy sources.

Quantitative finance: With strong mathematical and analytic skills, physicists are a great fit for the financial world, and are often in high demand in quantitative finance in particular. Meet five physicists who pivoted to a career in finance, and explore what physics skills they use day to day.

Intelligence and cyber security: If a challenging but rewarding career is what you are looking for, you may want to consider a role in security. Here you can find out more about the careers of two leaders from GCHQ – the UK’s intelligence, security and cyber agency – with a background in physics.

Medical physics: Medical physicists have a wide variety of roles across academia and industry. From clinical research and medical imaging to computational simulations and testing new scanners, many job options for medical physicists around the world are included here.

Quantum: The quantum sector is thriving and there are numerous roles across the four main pillars of quantum computing; quantum simulation; quantum communication; and quantum sensing and metrology. From industry to academia, government and policy, and education; there are many ways to join the revolution.

Nuclear energy: With the push away from fossil fuels, there is a shortage of skills in the nuclear power sector. Here we speak to six physicists working across the nuclear energy industry – from design and construction, to safety and waste and beyond – highlighting how a background in physics can open many doors in this expanding sector.

The post Cosmic time capsules: the search for pristine comets appeared first on Physics World.

The overall picture for all of you graduating with a degree in physics is positive. Physicists all over the world are keen to help solve some of humanity’s biggest challenges and help further our understanding of the universe at large. We hope that all of the resources above – alongside the annual Physics World Careers guide, the Physics World Jobs Hub and the Physics World LinkedIn page – will give you the headstart you need in planning your path and building a fulfilling career.

You can sign up to our bi-monthly careers newsletter from your account area on Physics World. Just click on My Alerts and tick the box to start receiving it

The post From student to scientist – how to build a career with physics appeared first on Physics World.

Hot ancient galaxy cluster challenges current cosmological models

Anna Demming — Fri, 23 Jan 2026 11:30:13 +0000

Could a mirror world – in which every type of elementary particle has a corresponding mirror particle – exist in parallel to our ordinary world? For now, the answer is probably no, but in exploring this question, physicists at the Ultracold Neutron (UCN) Physics Group at the Paul Scherrer Institute (PSI) in Switzerland, say they have refuted this hypothesis with the best precision yet. Their work, which involved looking for so-called neutron-to-mirror-neutron transitions, also excludes mirror neutrons as potential components of dark matter, the mysterious substance thought to make up over 25% of the universe’s mass. Dark matter has never been detected directly, but its existence is inferred through observed gravitational interactions.

Theoretical physicists put forward the idea of a mirror world as long ago as the 1950s to address problems related to parity symmetry conservation in particle physics. Here, a set of mirror particles would exist as exact duplicates of their ordinary particle counterparts except that their so-called handedness would be reversed. In this picture, particles like the electron e, proton p and neutron n have mirror partners denoted by e′, p′ and n′. These mirror particles would have almost the same mass as the ordinary particles.

Not easy to detect

Finding proof for the existence of this mirror matter is important as it could account for dark matter – provided that during the evolution of the universe mirror matter was cooler than ordinary matter. Mirror matter is not easy to detect, however, because mirror particles are predicted to interact with ordinary matter in only two ways. The first is via the force of gravity and the second is through the rare oscillation of neutral particles such as neutrons that “mix” with their mass-degenerate mirror partners. This, explains Bernhard Lauss, one of the physicists at the PSI’s Center for Neutron and Muon Sciences who led this new study, means that ordinary neutrons might, on very rare occasions, turn into their mirror particles and simply “vanish” from our world. The time period up to this event is known as the n−n′ oscillation time, and afterwards a neutron could even reappear as if out of nowhere.

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Neutron-to-mirror-neutron mixing has been predicted to have an n−n′ oscillation time as small as few tens of seconds, but it is not easily detectable because it is suppressed by environmental factors such as the presence of ordinary and/or mirror matter or of ordinary and/or mirror magnetic fields.

In recent years, researchers have been trying to reduce these environmental effects by studying neutrons cooled to extremely low temperatures. There are only a few laboratories around the world that can produce such ultracold neutrons at high regular flux. One is the Institut Laue–Langevin (ILL) in Grenoble, France, and another is the PSI.

Unexplored regions

The results from a series of experiments at the ILL in the past 20 years conducted at various magnetic fields were interpreted as being anomalous signals in the range of magnetic fields at which n−n′ oscillations could take place, thereby rekindling interest in the existence of mirror neutrons. More recently, the nEDM collaboration at PSI excluded a big part of this magnetic field range, but some magnetic field regions remain unexplored.

In the latest work, Lauss together with his colleague Géza Zsigmond and co-workers from PSI, the ETH Zurich and the Jagiellonian University in Krakow used ultracold neutrons from the PSI UCN source produced via a technique called superthermal moderation in a deuterium crystal cooled down to a temperature of 5 K. The researchers trapped these neutrons in a non-magnetic vessel made of stainless steel under vacuum. They were able to trap an unprecedented number of neutrons – on the order of 25 billion in all – something that allowed them to significantly improve the sensitivity of such experiments. A set of eight rectangular coils surrounding the storage vessel was used to generate a magnetic field that could be precisely controlled and scanned over two orders of magnitude, from 5–109 µT.

The team released around 1.5 million neutrons from the storage vessel into a gas-electron-multiplier based UCN-detector every six minutes to count how many neutrons remained in the tank after being stored there for 200 s. The researchers repeated the process over a period of several months, gradually varying the strength and flipping the direction of the magnetic field to scan all the relevant fields over which oscillations between neutrons and mirror neutrons are expected to occur. Finally, they performed complex computational simulations on the EULER cluster at the ETH Zurich to predict theoretical probabilities of n-n’ transitions that they then compared with the neutron losses they measured.

New limits set

The result? The researchers say they saw no evidence for such oscillations under the tested conditions. This finding, explains Lauss, means that there is a “very high probability” that previous speculations about the transformation of neutron particles into their mirror counterparts can be ruled out and that new limits for the n−n′ oscillation time constant have now been set. “Indeed, we have excluded the parameter space previously claimed for potential signals to 99.98 %,” he explains.

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“The result therefore also excludes mirror neutrons as relevant dark matter particles,” Lauss tells Physics World.

Despite the existing limits already being very tight, Lauss, Zsigmond and their colleagues say they now plan to study the n−n′ transitions theoretically expected at zero mirror-magnetic fields to establish even more stringent limits. “Improving sensitivity further will be very challenging though, and perhaps even impossible,” admits Zsigmond. “A twofold increase, for example, will require 16 times more neutrons because the sensitivity of the experiment scales with the fourth root of the neutron counts.”

The post No show again for mirror neutrons appeared first on Physics World.

Laser fusion: Focused Energy charts a course to commercial viability

Hamish Johnston — Thu, 22 Jan 2026 15:01:44 +0000

This episode of the Physics World Weekly podcast features a conversation with the plasma physicist Debbie Callahan who is chief strategy officer at Focused Energy – a California and Germany based fusion-energy startup. Prior to that she spent 35 years working at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory in the US.

Focused Energy is developing a commercial system for generating energy from the laser-driven fusion of hydrogen isotopes. Callahan describes LightHouse, which is the company’s design for a laser-fusion power plant, and Pearl, which is the firm’s deuterium–tritium fuel capsule.

Callahan talks about the challenges and rewards of working in the fusion industry and also calls on early-career physicists to consider careers in this burgeoning sector.

The post Laser fusion: Focused Energy charts a course to commercial viability appeared first on Physics World.

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Fancy some more? Check out our puzzles page.

The post Quiz of the week: how will the new ‘AstroRad’ vest be of benefit to astronauts? appeared first on Physics World.

Fuel cell catalyst requirements for heavy-duty vehicle applications

No Author — Thu, 22 Jan 2026 11:25:19 +0000

Unconventional superconductors are poorly understood materials with exceptionally useful properties. One example is their response to magnetic fields. In conventional superconductors, applied magnetic fields suppress superconductivity by either breaking up the paired electrons that facilitate it (Cooper pairs) or introducing magnetic flux which introduce resistance when it moves through the material. However, in a few unconventional materials, competition between ferromagnetic ordering, where the magnetic moments align to point in the same direction, and superconducting ordering, where paired electron moments point in opposite directions, can lead to a phenomenon known as re-entrant superconductivity (RSC). This is where, in an applied field, the magnetic ordering will at first destroy superconductivity, but when the field increases further, the superconductivity reappears.

An international team of physicists led by Denis Maryenko of Japan’s RIKEN Center for Emergent Matter Science has now observed this phenomenon for the first time in a two-dimensional (2D) unconventional superconductor. “We did not look for the RSC, and it was extremely surprising that we saw that,” Maryenko tells Physics World.

2D or not 2D

RSC has previously been observed in three-dimensional ferromagnetic materials such as CeRh ₂ As ₂ , organic superconductors and possibly in so-called heavy fermion com pounds such as UTe ₂ . However, 2D materials have several advantages over 3D ones when it comes to superconductivity. For example, in the conductor MoS ₂ , the material’s electronic band structure and spin-orbit coupling (SOC) combine to keep the electron spins pointing in a direction perpendicular to the sample’s surface. This locking greatly increases the value of the upper critical field, which is the maximum magnetic field at which superconductivity can persist.

Since 2D superconductivity had previously been observed at interfaces between KTaO ₃ and other materials, the RIKEN team took this as a starting point. “Our approach was to grow LaTiO₃, [since] that has good lattice matching [to KTaO₃], which is beneficial for epitaxial growth,” Maryenko explains.

Writing in Science Advances, the physicists describe how they performed magnetotransport measurements on their LaTiO₃/KTaO₃heterostructures to understand how these samples behaved in the presence of increasingly large applied magnetic fields. “We just wanted to see how the critical magnetic field behaves as a function of temperature, but suddenly we started seeing something else emerging at a rather low field: a resistive peak that seemed to separate two superconducting regions,” Maryenko says.

Reentrant superconducting response: A plot of the interface resistance as a function of magnetic field and gate voltage, showing reentrant superconductivity at a magnetic field of around 0.9 T. (Courtesy: D Maryenko et al. Science Advances 12 26 DOI: 10.1126/sciadv.aeg0460)

This cusp, he explains, appears at a magnetic field B^∗ of 0.9 T with zero resistance measured at both lower and higher applied fields. In this experiment, B^∗ is independent of temperature and the concentration of charge carriers, which Maryenko and colleagues controlled experimentally by tuning a gate voltage across the interface.

Explaining re-entrant superconductivity

The researchers considered several possible explanations for the RSC, including Zeeman splitting, orbital effects and something called the Jaccarino-Peter effect, where internal and external magnetic fields compensate for each other and cancel out.

To identify the correct explanation, Igor Maznichenko and Sergey Ostanin from Martin Luther University in Germany and Arthur Ernst from Johannes Kepler University in Austria performed ab initio calculations to determine the electron band structure for the interface. These calculations identified the presence of a so-called Van Hove singularity, where for certain momenta, the electrons will have very high density of states.

Then, Vitalii Dugaev from Rzeszów University of Technology in Poland and Evgeny Ya Sherman at the University of the Basque Country in Spain developed a SOC-based model, taking inspiration from symmetry arguments and the ab initio band structure calculations. In the absence of an applied field, they found that there is a p ↔−p symmetry in the bands. This means that electrons with opposite momenta will have the same energy, so two electrons that form a Cooper pair, and have the same energy, have a total momentum equal to zero. In other words, the system favours spin-singlet Cooper pairs which form easily.

Applying a field breaks this symmetry, thereby reducing the Cooper pairing efficiency and decreasing the critical temperature T_c for the onset of superconductivity. On the other hand, the applied field also shifts the electrons closer towards the Van Hove singularity, increases the density of states and increases T_c. The combination of these opposing effects results in a minima appearing in T_c(B), hence RSC. The discovery of RSC in these materials establishes the system as a robust platform for studying unconventional superconductivity in 2D systems.

The post Magnetic field first kills superconductor, then brings it back to life appeared first on Physics World.

Ask me anything: Mažena Mackoit-Sinkevičienė – ‘Above all, curiosity drives everything’

Tushna Commissariat — Thu, 22 Jan 2026 11:00:23 +0000

What skills do you use every day in your job?

Much of my time is spent trying to build and refine models in quantum optics, usually with just a pencil, paper and a computer. This requires an ability to sit with difficult concepts for a long time, sometimes far longer than is comfortable, until they finally reveal their structure.

Good communication is equally essential – I teach students; collaborate with colleagues from different subfields; and translate complex ideas into accessible language for the broader public. Modern physics connects with many different fields, so being flexible and open-minded matters as much as knowing the technical details. Above all, curiosity drives everything. When I don’t understand something, that uncertainty becomes my strongest motivation to keep going.

What do you like best and least about your job?

What I like the best is the sense of discovery – the moment when a problem that has evaded understanding for weeks suddenly becomes clear. Those flashes of insight feel like hearing the quiet whisper of nature itself. They are rare, but they bring along a joy that is hard to find elsewhere.

+ The UK’s Science and Technology Facilities Council (STFC) recently announced funding cuts to a range of physics and astronomy projects as it seeks to reduce costs. One of the most high-profile casualties is e-MERLIN, a network of seven radio telescopes spread across the UK, including the iconic Lovell Telescope at Jodrell Bank.

I also value the opportunity to guide the next generation of physicists, whether in the university classroom or through public science communication. Teaching brings a different kind of fulfilment: witnessing students develop confidence, curiosity and a genuine love for physics.

What I like the least is the inherent uncertainty of research. Questions do not promise favourable answers, and progress is rarely linear. Fortunately, I have come to see this lack of balance not as a weakness but as a source of power that forces growth, new perspectives, and ultimately deeper understanding.

What do you know today that you wish you knew when you were starting out in your career?

I wish I had known that feeling lost is not a sign of inadequacy but a natural part of doing physics at a high level. Not understanding something can be the greatest motivator, provided one is willing to invest time and effort. Passion and curiosity matter far more than innate brilliance. If I had realized earlier that steady dedication can carry you farther than talent alone, I would have embraced uncertainty with much more confidence.

The post Ask me anything: Mažena Mackoit-Sinkevičienė – ‘Above all, curiosity drives everything’ appeared first on Physics World.

To discover what the cuts could mean for UK science and the livelihoods of those affected, podcast host Andrew Glester caught up with two astronomers at Jodrell Bank: Simon Garrington, e-MERLIN director, and David Williams-Baldwin, an e-MERLIN research support scientist.

They discuss why the cuts have caused such alarm among scientists, how the UK astronomy community is mobilizing in opposition, and why the consequences could extend far beyond Jodrell Bank.

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e-MERLIN combines signals from its telescopes to produce sharp radio images of the Universe – with a resolution comparable to that of the Hubble Space Telescope. As things stand, funding for the telescope array will run out in March 2028, putting the future of the network and scientific operations at Jodrell Bank in doubt.

It’s an uncertain time for an observatory that was granted UNESCO World Heritage status in July 2019 for its historical contributions and its technical and scientific ingenuity since the 1940s.

An STFC spokesperson emphasises that Jodrell Bank is “not closing” and “will continue to play an important role in UK science”. This includes the Square Kilometre Array Observatory that has its headquarters at Jodrell Bank as well as other radio astronomy research projects in the UK and elsewhere.

“We recognise the strength of feeling about Jodrell Bank and the e-MERLIN network, and the contribution they have made to UK science. The achievements of the scientists, engineers and staff who have supported e-MERLIN over many years are widely respected across the research community,” they add. “We are focusing on the next generation of radio astronomy to ensure UK researchers continue to be at the forefront of the field. Rising cost pressures mean that we have had to make difficult choices about STFC funding to make sure we are able to fund world class research sustainably into the future.”

The post With e-MERLIN facing the axe, what next for Jodrell Bank and UK astronomy? appeared first on Physics World.

Modelling wavefunction collapse as a continuous flow yields insights on the nature of measurement

Vijit Nautiyal — Thu, 22 Jan 2026 09:30:19 +0000

Earthquakes that propagate at higher speeds make the ground move more than it would in slower but otherwise comparable earthquakes, say geophysicists. Using physics-based models, Mohamed Abdelmeguid and colleagues at the California Institute of Technology in the US showed that so-called “supershear” ruptures produce stronger and longer-duration ground motion than equivalent subshear ruptures. Because models of ground motion that underpin infrastructure standards do not account for this effect, these models may need to be updated to accurately describe hazards such as the 2025 Myanmar earthquake, which produced supershear ruptures in both directions.

Geophysicists have identified two categories of earthquake based on how fast their ruptures propagate through the Earth’s crust. Shear waves, or S waves, travel at certain expected velocities (the shear-wave velocity) depending on the stiffness and density of the ground. When a rupture travels faster than the shear-wave velocity of the surrounding ground, it is termed a supershear earthquake. Otherwise, it is subshear.

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Although Abdelmeguid notes that supershear ruptures were first predicted theoretically in the 1970s, and have subsequently been observed in both laboratory experiments and the real world, most previous studies focused on their underlying mechanisms and the transition from subshear to supershear. The new study, which appears in the Bulletin of the Seismological Society of America, goes a step further by examining how the ground motion in a supershear quake differs from that of an otherwise comparable subshear one. The question is relevant, Abdelmeguid says, because nearly 36% of strike-slip earthquakes during the past 15 years contained supershear rupture, yet existing models do not factor it in.

Supershear simulations

To address this gap, Abdelmeguid and colleagues developed a dynamic rupture model that generates simulated ground motion data and used it to identify the characteristics of supershear earthquakes. They found that prolonged supershear propagation produces what they term “a distinct spatial pattern of stronger and longer-duration shaking”. However, episodic supershear segments, where rupture speed intermittently changes between supershear and subshear, produce ground motion similar to subshear ruptures.

Simulations like these are important because some supershear rupture scenarios are poorly represented in the observational record. This record is used to develop ground motion models, so simulations can “reveal physical dependencies that may not be apparent from existing observations,” Abdelmeguid says.

Characterizing the 2025 Myanmar earthquake

The 2025 Myanmar earthquake – a supershear quake in which many regions experienced higher than expected ground shaking – is a case in point. It occurred on the 1200-kilometre-long Sagaing Fault, which lies at the boundary of the Burma microplate and the Sunda plate and is not far from Mandalay, the country’s second-largest city. At magnitude 7.7, it was the largest earthquake in Myanmar in over a century, and the long rupture meant that large parts of Myanmar and Thailand were affected, with thousands of deaths and injuries as well as severe damage to infrastructure.

Initial studies were inconclusive about whether this earthquake’s rupture exhibited intermittent or sustained supershear speed. This lack of consensus is partly because recording intermittent supershear rupture is challenging when near-fault sensors are sparse, as is the case in Myanmar (and indeed most countries, with notable exceptions such as Japan, Taiwan, New Zealand and parts of the US).

A new study published in PNAS addresses this question. Using satellite earth observations, teleseismic data and CCTV footage as well as the available near-fault seismic sensor data, researchers led by Lingling Ye at the Southern University of Science and Technology (SUSTech) in China modelled the rupture process of the Myanmar quake. The result, Ye says, is a “well-resolved rupture process” that “reveals previously unrecognized dynamic rupture features”. Notably, the team’s simulations showed that the rupture transitioned between supershear and subshear as it tore through around 460 kilometres of the country.

Influence of geometry and stress distribution

To understand the cause of these variations, the researchers examined the geometry and stress distribution along the fault. Based on an existing fault model, they calculated a parameter called fault misalignment, which acts as an indicator for irregularities in the fault geometry. Higher fault misalignment, for example, indicates higher bends and branches in the fault.

When the researchers overlaid fault misalignment with the observed rupture speed, they noticed that supershear speeds coincided with fault stretches that had lower misalignment. For fault stretches with higher misalignment, subshear speed prevailed, meaning that the rupture decelerates at locations with high fault misalignment, transitioning from supershear to subshear. The researchers also found that the rupture speed, whether supershear or subshear, responded to the varying levels of local stress, with higher stress levels inducing faster rupture speed.

Although not unique in exhibiting supershear behaviour, the 2025 Myanmar earthquake rupture propagated away from the epicentre on both sides, travelling around 80 kilometres to the north and 380 kilometres to the south. Initial studies debated whether the ruptures on both sides were supershear. The researchers found that the northern rupture propagation was not supershear and claim that its shorter rupture length is caused by a combination of the fault’s complex structure and low accumulated stress resulting from the magnitude 6.8 earthquake that struck in 2012.

“Every earthquake has unique behaviour”

In future work, Ye is eager to revisit the 2023 Turkey doublet earthquakes, which she says have many more near-fault strong motion observations than the 2025 Myanmar quake, as well as a now well characterized complex fault system. “Every earthquake has unique behaviour,” she says. “Determining the key features that control their rupture processes is still underway.”

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For Abdelmeguid, who recently started his own research group at the University of Houston, US, understanding these complex rupture processes is important because it will ultimately improve our understanding of geophysical processes and the ground motion models that are used for engineering applications. “We are currently extending this work to examine ground motions generated by ruptures on more complex faults, including cases in which fault geometry and heterogeneity influence both ground motion and the dynamic process, as observed during the multiple earthquakes,” he tells Physics World.

This article was amended on 2 September 2026 to clarify the nature of the rupture propagation in the 2025 Myanmar earthquake. The researchers found that the northern rupture was subshear, not supershear as originally stated.

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NPL unveils miniature atomic fountain clock

Hamish Johnston — Wed, 21 Jan 2026 17:23:16 +0000

An “invisibility cloak” for cells The top row of photos, taken with a scanning electron microscope, shows uncoated cell clusters (islets). The bottom row shows a series of islets covered in a thin film that hides the donor cells from the body’s immune response, potentially offering a novel approach to treating diabetes. Scale bar: 0.05 mm. (Courtesy: Provided by Kyungsene Lee)

Islet transplantation, in which insulin-producing islet cells from a donor are implanted into a patient’s liver, is a promising therapy for type 1 diabetes. To prevent rejection of the donated cells, however, recipients need to continuously take immunosuppression drugs. Using a new type of cell encapsulation, researchers at The Pennsylvania State University demonstrated that diabetic mice could maintain normal blood glucose levels for 100 days, without requiring immunosuppressants. This represents a substantially longer time period than traditional cell therapies for diabetes.

The Penn State researchers developed their cell encapsulation process based on the molecular characteristics of the zona pellucida, a thin membrane that coats mammalian eggs. Once an egg is fertilized, biochemical reactions lead to hardening of the zona pellucida, which acts as a protective shield during embryo development. Here, biomimetic zona pellucida (BZP) encapsulation serves to hide the donor islets from the body’s immune system.

Pancreatic islets are clusters of five types of cells that work in tandem to regulate insulin and sugar levels in the body and prevent severe insulin deficiency. Islets harvested from healthy pancreases of deceased organ donors were first transplanted into Type 1 diabetes mellitus patients in 1974.

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And in 2000, a landmark procedure increasing the mass of islets transferred and using steroid-free immunosuppression regimens was introduced by the University of Alberta in Edmonton, offering the hope of curing diabetes. But when implemented clinically, only 24% of recipients achieved insulin independence at 28 months with the Edmonton protocol.

Research on islet implantation continued unabated, particularly initiatives in islet encapsulation, using semi-permeable membranes to allow the entry of oxygen and nutrients and prevent the entrance of immune response cells. Most current work in this area uses large, 1.5 mm capsules. The Penn State team took an opposite tack: creating a thin 20-µm hydrogel capsule that spontaneously generates on the cell surface with 100% encapsulation efficiency.

Protection from immune attack

Principal investigator Yong Wang and colleagues spent eight years developing an ultrathin hydrogel layer that effectively lays against the curved edge of living cells or cell clusters without impacting their functionality. The islet encapsulation process takes place spontaneously in aqueous solutions under physiological conditions, without exposure to harsh physical, chemical or biological factors, ensuring that BZP development on the cell membrane does not cause any loss of cellular viability or function.

Corresponding author The research is led by Yong Wang, professor of biomedical engineering at Penn State. (Courtesy: Kate Myers/Penn State)

Writing in Nature Biomedical Engineering, the researchers explain that they emulated the biological processes that harden the zona pellucida on a fertilized egg (calcium ion-induced glycoprotein cleavage, assembly and crosslinking on the egg surface). In spite of its thinness, the BZP protects the cell as effectively as the much larger 1.5 mm diameter capsules.

The small capsule size significantly reduces the potential transplantation volume, improving an organ’s ability to receive and accommodate the large number of islets needed to be effective. When coating a 100-µm islet, for example, a 20-µm-thick BZP uses only 1/71 of the polymer volume of a 500-µm microcapsule. The researchers also suggest that the reduced polymer volume used for cell protection by the thin capsule may be a safety advantage of BZP compared to larger capsules.

In vivo assessment

The researchers first examined whether BZP could reduce the level of foreign body response to polystyrene microparticles injected into the peritoneal cavities of mice. Compared with uncoated microparticles, the BZP-coated particles induced a lower immune system response. They examined BZP synthesized using two types of alginate (involved in crosslinking reactions during BZP formation and hardening): chemically modified ultrapure alginate (BZP-U) and regular alginate (BZP-R). Tests in mice verified that BZP-U significantly mitigated the foreign body response compared with BZP-R encapsulation.

Immunocompetent diabetic mice treated with BZP-U-coated islets had their blood sugar restored to healthy levels within seven days. Additionally, the majority stayed diabetes free for over 100 days without continuously needing systemic immunosuppression. By comparison, mice treated with uncoated islets could not maintain healthy blood sugar levels for more than seven days.

In addition to effectively regulating blood glucose levels, one of the biggest advantages of the BZP approach is that it eliminates the need for long-term systemic immunosuppression. Lantidra, the only islet transplantation treatment for Type 1 diabetes cleared by the US Food and Drug Administration, requires continuous immunosuppressants to stop immune system attacks. Such long-term immunosuppressant use can lead to increased risk of infection and other serious health issues, including cancer.

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Wang and colleagues plan to further study the BZP approach to better understand the specific duration of resistance each islet transplant may offer, as well as its effect in large animals.

“Large animal studies will be necessary to fully demonstrate their potential in cell transplantation,” the researchers write. “When large animals are used, one needs to examine not only glucose levels but also other key biomarkers. Moreover, the long-term immune responses to BZP and BZP-encapsulated cells warrant further investigation to yield deeper insights into BZP optimization and improvement.”

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Shining laser light on a material produces subtle changes in its magnetic properties

Isabelle Dumé — Wed, 21 Jan 2026 14:00:49 +0000

Researchers in Switzerland have found an unexpected new use for an optical technique commonly used in silicon chip manufacturing. By shining a focused laser beam onto a sample of material, a team at the Paul Scherrer Institute (PSI) and ETH Zürich showed that it was possible to change the material’s magnetic properties on a scale of nanometres – essentially “writing” these magnetic properties into the sample in the same way as photolithography etches patterns onto wafers. The discovery could have applications for novel forms of computer memory as well as fundamental research.

In standard photolithography – the workhorse of the modern chip manufacturing industry – a light beam passes through a transmission mask and projects an image of the mask’s light-absorption pattern onto a (usually silicon) wafer. The wafer itself is covered with a photosensitive polymer called a resist. Changing the intensity of the light leads to different exposure levels in the resist-covered material, making it possible to create finely detailed structures.

In the new work, Laura Heyderman and colleagues in PSI-ETH Zürich’s joint Mesoscopic System group began by placing a thin film of a magnetic material in a standard photolithography machine, but without a photoresist. They then scanned a focused laser beam over the surface of the sample while modulating the beam’s wavelength of 405 nm to deliver varying intensities of light. This process is known as direct write laser annealing (DWLA), and it makes it possible to heat areas of the sample that measure just 150 nm across.

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In each heated area, thermal energy from the laser is deposited at the surface and partially absorbed by the film down to a depth of around 100 nm). The remainder dissipates through a silicon substrate coated in 300-nm-thick silicon oxide. However, the thermal conductivity of this substrate is low, which maximizes the temperature increase in the film for a given laser fluence. The researchers also sought to keep the temperature increase as uniform as possible by using thin-film heterostructures with a total thickness of less than 20 nm.

Crystallization and interdiffusion effects

Members of the PSI-ETH Zürich team applied this technique to several technologically important magnetic thin-film systems, including ferromagnetic CoFeB/MgO, ferrimagnetic CoGd and synthetic antiferromagnets composed of Co/Cr, Co/Ta or CoFeB/Pt/Ru. They found that DWLA induces both crystallization and interdiffusion effects in these materials. During crystallization, the orientation of the sample’s magnetic moments gradually changes, while interdiffusion alters the magnetic exchange coupling between the layers of the structures.

The researchers say that both phenomena could have interesting applications. The magnetized regions in the structures could be used in data storage, for example, with the direction of the magnetization (“up” or “down”) corresponding to the “1” or “0” of a bit of data. In conventional data-storage systems, these bits are switched with a magnetic field, but team member Jeffrey Brock explains that the new technique allows electric currents to be used instead. This is advantageous because electric currents are easier to produce than magnetic fields, while data storage devices switched with electricity are both faster and capable of packing more data into a given space.

Team member Lauren Riddiford says the new work builds on previous studies by members of the same group, which showed it was possible to make devices suitable for computer memory by locally patterning magnetic properties. “The trick we used here was to locally oxidize the topmost layer in a magnetic multilayer,” she explains. “However, we found that this works only in a few systems and only produces abrupt changes in the material properties. We were therefore brainstorming possible alternative methods to create gradual, smooth gradients in material properties, which would open possibilities to even more exciting applications and realized that we could perform local annealing with a laser originally made for patterning polymer resist layers for photolithography.”

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Riddiford adds that the method proved so fast and simple to implement that the team’s main challenge was to investigate all the material changes it produced. Physical characterization methods for ultrathin films can be slow and difficult, she tells Physics World.

The researchers, who describe their technique in Nature Communications, now hope to use it to develop structures that are compatible with current chip-manufacturing technology. “Beyond magnetism, our approach can be used to locally modify the properties of any material that undergoes changes when heated, so we hope researchers using thin films for many different devices – electronic, superconducting, optical, microfluidic and so on – could use this technique to design desired functionalities,” Riddiford says. “We are looking forward to seeing where this method will be implemented next, whether in magnetic or non-magnetic materials, and what kind of applications it might bring.”

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+ Word wave puzzle no.8 + https://physicsworld.com/a/word-wave-puzzle-no-8/ + Thu, 27 Aug 2026 13:30:42 +0000 + + + + + https://physicsworld.com/?p=129950 + Can you work out the word in this puzzle, which relates to a recent Physics World article?

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The obscure physics theory that helped Chinese science emerge from the shadows

Robert P Crease — Wed, 21 Jan 2026 11:00:52 +0000

“The Straton Model of elementary particles had very limited influence in the West,” said Jinyan Liu as she sat with me in a quiet corner of the CERN cafeteria. Liu, who I caught up with during a break in a recent conference on the history of particle physics, was referring to a particular model of elementary particle physics first put together in China in the mid-1960s. The Straton Model was, and still largely is, unknown outside that country. “But it was an essential step forward,” Liu added, “for Chinese physicists in joining the international community.”

Liu was at CERN to give a talk on how Chinese theorists redirected their research efforts in the years after the Cultural Revolution, which ended in 1976. They switched from the Straton Model, which was a politically infused theory of matter favoured by Mao Zedong, the founder of the People’s Republic of China, to mainstream particle physics as practised by the rest of the world. It’s easy to portray the move as the long-overdue moment when Chinese scientists resumed their “real” physics research. But, Liu told me, “actually it was much more complicated”.

A physicist by training, Liu received her PhD on contemporary theories of spontaneous charge-parity (CP) violation from the Institute of Theoretical Physics at the Chinese Academy of Sciences (CAS) in 2013. She then switched to the CAS Institute for the History of Natural Sciences, where she was its first member with a physics PhD. Her initial research topic was the history and development of the Straton Model.

The model is essentially a theory of the structure of hadrons – either baryons (such as protons and neutrons) or mesons (such as pions and kaons). But the model’s origins are as improbable as they are labyrinthine. Mao, who had a keen interest in natural science, was convinced that matter was infinitely divisible, and in 1963 he came across an article by the Marxist-inspired Japanese physicist Shoichi Sakata (1911–1970).

First published in Japanese in 1961 and later translated into Russian, Sakata’s paper was entitled “Dialogues concerning a new view of elementary particles”. It restated Sakata’s belief, which he had been working on since the 1950s, that hadrons are made of smaller constituents – “elementary particles are not the ultimate elements of matter” as he put it. With some Chinese scholars back then still paying close attention to publications from the Soviet Union, their former political and ideological ally, that paper was then translated into Chinese.

Mao Zedong was engrossed in Shoichi Sakata’s paper, for it seemed to offer scientific support for his own views.
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This version appeared in the Bulletin of the Studies of Dialectics of Nature in 1963. Mao, who received an issue of that bulletin from his son-in-law, was engrossed in Sakata’s paper, for it seemed to offer scientific support for his own views. Sakata’s article – both in the original Japanese and now in Chinese – cited Friedrich Engels’ view that matter has numerous stages of discrete but qualitatively different parts. In addition, it quoted Lenin’s remark that “even the electron is inexhaustible”.

A wider dimension

“International politics now also entered,” Liu told me, as we discussed the issue further at CERN. A split between China and the Soviet Union had begun to open up in the late 1950s, with Mao breaking off relations with the Soviet Union and starting to establish non-governmental science and technology exchanges between China and Japan. Indeed, when China hosted the Peking Symposium of foreign scientists in 1964, Japan brought the biggest delegation, with Sakata as its leader.

At the event, Mao personally congratulated Sakata on his theory. It was, Sakata later recalled, “the most unforgettable moment of my journey to China”. In 1965, Sakata’s paper was retranslated from the Japanese original, with an annotated version published in Red Flag and the newspaper Renmin ribao, or “People’s Daily”, both official organs of the Chinese Communist Party.

Chinese physicists realized that they could capitalize on Mao’s enthusiasm to make elementary particle physics a legitimate research direction.
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Chinese physicists, who had been assigned to work on the atomic bomb and other research deemed important by the Communist Party, now started to take note. Uninterested in philosophy, they realized that they could capitalize on Mao’s enthusiasm to make elementary particle physics a legitimate research direction.

As a result, 39 members of CAS, Peking University and the University of Science and Technology of China formed the Beijing Elementary Particle Group. Between 1965 and 1966, they wrote dozens of papers on a model of hadrons inspired by both Sakata’s work and quark theory based on the available experimental data. It was dubbed the Straton Model because it involved layers or “strata” of particles nested in each other.

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Liu has interviewed most surviving members of the group and studied details of the model. It differed from the model being developed at the time by the US theorist Murray Gell-Mann, which saw quarks as not physical but mathematical elements. As Liu discovered, Chinese particle physicists were now given resources they’d never had before. In particular, they could use computers, which until then had been devoted to urgent national defence work. “To be honest,” Liu chuckled, “the elementary particle physicists didn’t use computers much, but at least they were made available.”

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The high-water mark for the Straton Model occurred in July 1966 when members of the Beijing Elementary Particle Group presented it at a summer physics colloquium organized by the China Association for Science and Technology. The opening ceremony was held in Tiananmen Square, in what was then China’s biggest conference centre, with attendees including Abdus Salam from Imperial College London. The only high-profile figure to be invited from the West, Salam was deemed acceptable because he was science advisor to the president of Pakistan, a country considered outside the western orbit.

The proceedings of the colloquium were later published as “Research on the theory of elementary particles carried out under the brilliant illumination of Mao Tse-Tung’s thought”. Its introduction was what Liu calls a “militant document” – designed to reinforce the idea that the authors were carrying Mao’s thought into scientific research to repudiate “decadent feudal, bourgeois and revisionist ideologies”.

Participants in Beijing had expected to make their advances known internationally by publishing the proceedings in English. But the Cultural Revolution had just begun two months before, and publications in English were forbidden. “As a result,” Liu told me, “the model had very limited influence outside China.” Sakata, however, had an important influence on Japanese theorists having co-authored the key paper on neutrino flavour oscillation (Prog. Theoretical. Physics 28 870).

A resurfaced effort

In recent years, Liu has shed new light on the Straton Model, writing a paper in the journal Chinese Annals of History of Science and Technology (2 85). In 2022, she also published a Chinese-language book entitled Constructing a Theory of Hadron Structure: Chinese Physicists’ Straton Model, which describes the downfall of the model after 1966. None of its predicted material particles appeared, though a candidate event once occurred in a cosmic ray observatory in the south of China.

By 1976, quantum chromodynamics (QCD) had convincingly emerged as the established model of hadrons. The effective end of the Straton Model took place at a conference in January 1980 in Conghua, near Hong Kong. Hung-Yuan Tzu, one of the key leaders of the Beijing Group, gave a paper entitled “Reminiscences of the Straton Model”, signalling that physics had moved on.

During our meeting at CERN, Liu showed me photos of the 1980 event. “It was a very important conference in the history of Chinese physics,” she said, “the first opening to Chinese physicists in the West”. Visits by Chinese expatriates were organized by Tsung-Dao Lee and Chen-Ning Yang, who shared the 1957 Nobel Prize for Physics for their work on parity violation.

The critical point

It is easy for westerners to mock the Straton Model; Sheldon Glashow once referred to it as about “Maons”. But Liu sees it as significant research that had many unexpected consequences, such as helping to advance physics research in China. “It gave physicists a way to pursue quantum field theory without having to do national defence work”.

The model also trained young researchers in particle physics and honed their research competence. After the post-Cultural Revolution reform and its opening to the West, these physicists could then integrate into the international community. “The story,” Liu said, “shows how ingeniously the Chinese physicists adapted to the political situation.”

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A surprising critical state emerges in active nematic materials

Lorna Brigham — Wed, 21 Jan 2026 07:47:29 +0000

Nematics are materials made of rod‑like particles that tend to align in the same direction. In active nematics, this alignment is constantly disrupted and renewed because the particles are driven by internal biological or chemical energy. As the orientation field twists and reorganises, it creates topological defects-points where the alignment breaks down. These defects are central to the collective behaviour of active matter, shaping flows, patterns, and self‑organisation.

In this work, the researchers identify an active topological phase transition that separates two distinct regimes of defect organisation. As the system approaches this transition from below, the dynamics slow dramatically: the relaxation of defect density becomes sluggish, fluctuations in the number of defects grow in amplitude and lifetime, and the system becomes increasingly sensitive to small changes in activity. At the critical point, defects begin to interact over long distances, with correlation lengths that grow with system size. This behaviour produces a striking dual‑scaling pattern, defect fluctuations appear uniform at small scales but become anti‑hyperuniform at larger scales, meaning that the number of defects varies far more than expected from a random distribution.

A key finding is that this anti‑hyperuniformity originates from defect clustering. Rather than forming ordered structures or undergoing phase separation, defects tend to appear near existing defects, creating multiscale clusters. This distinguishes the transition from well‑known defect‑unbinding processes such as the Berezinskii-Kosterlitz-Thouless transition in passive nematics or the nematic-isotropic transition in screened active systems. Above the critical activity, the system enters a defect‑laden turbulent state where defects are more uniformly distributed and correlations become short‑ranged and negative.

The researchers confirm these behaviours experimentally using large‑field‑of‑view measurements of endothelial cell monolayers which are the cells that line blood vessels. The same dual‑scaling behaviour, long‑range correlations, and clustering appear in these living tissues, demonstrating that the transition is robust across system sizes, parameter variations, frictional damping, and boundary conditions.

Read the full article

Anti-hyperuniform critical states of active topological defects

Simon Guldager Andersen et al 2025 Rep. Prog. Phys. 88 108101

Do you want to learn more about this topic?

Active phase separation: new phenomenology from non-equilibrium physics M E Cates and C Nardini (2025)

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Non-Abelian anyons: anything but easy

Paul Mabey — Wed, 21 Jan 2026 07:42:34 +0000

Topological quantum computing is a proposed approach to building quantum computers that aims to solve one of the biggest challenges in quantum technology: error correction.

In conventional quantum systems, qubits are extremely sensitive to their environment and even tiny disturbances can cause errors. Topological quantum computing addresses this by encoding information in the global properties of a system: the topology of certain quantum states.

These systems rely on the use of non-Abelian anyons, exotic quasiparticles that can exist in two-dimensional materials under special conditions.

The main challenge faced by this approach to quantum computing is the creation and control of these quasiparticles.

One possible source of non-Abelian anyons is the fractional quantum Hall state (FQH): an exotic state of matter which can exist at very low temperatures and high magnetic fields.

These states come in two forms: even-denominator and odd-denominator. Here, we’re interested in the even-denominator states – the more interesting but less well understood of the two.

In this latest work, researchers have observed this exotic state in gallium arsenide (GaAs) two-dimensional hole systems.

Typically, FQH states are isotropic, showing no preferred direction. Here, however, the team found states that are strongly anisotropic, suggesting that the system spontaneously breaks rotational symmetry.

This means that it forms a nematic phase – similar to liquid crystals – where molecules align along a direction without forming a rigid structure.

This spontaneous symmetry breaking adds complexity to the state and can influence how quasiparticles behave, interact, and move.

The observation of the existence of spontaneous nematicity in an even-denominator fractional quantum Hall state is the first of its kind.

Although there are many questions left to be answered, the properties of this system could be hugely important for topological quantum computers as well as other novel quantum technologies.

Read the full article

Even-denominator fractional quantum Hall states with spontaneously broken rotational symmetry – IOPscience

C. Wang et al 2025 Rep. Prog. Phys. 88 100501

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Physicist Norbert Holtkamp takes over as head of Fermilab

Michael Banks — Tue, 20 Jan 2026 17:49:05 +0000

Particle pioneer: One of Holtkamp’s main aims will be to oversee the completion of the $1.5bn Long-Baseline Neutrino Facility-Deep Underground Neutrino Experiment (courtesy: JJ Starr, Fermilab)

Particle physicist Norbert Holtkamp has been appointed the new director of Fermi National Accelerator Laboratory. He took up the position on 12 January, replacing Young-Kee Kim from the University of Chicago, who held the job on an interim basis following the resignation of Lia Merminga last year.

With a PhD in physics from the Technical University in Darmstadt, Germany, Holtkamp has managed large scientific projects throughout his career.

Holtkamp is the former deputy director of the SLAC National Accelerator Laboratory at Stanford University where he managedthe construction of the Linac Coherent Light Source upgrade, the world’s most powerful X-ray laser, along with more than $2bn of onsite construction projects.

Holtkamp also previously served as the principal deputy director general for the international fusion project ITER, which is currently under construction in Cadarache, France.

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Holtkamp worked at Fermilab between 1998 and 2001, where he worked on commissioning the Main Injector and also led a study on the feasibility of an intense neutrino source based on a muon storage ring.

One of Holtkamp’s main aims as Fermilab boss will be to oversee the completion of the $5bn Long-Baseline Neutrino Facility-Deep Underground Neutrino Experiment (LBNF-DUNE) at Fermilab, which is expected to come online towards the end of the decade.

LBNF-DUNE will study the properties of neutrinos in unprecedented detail, as well as the differences in behaviour between neutrinos and antineutrinos. The DUNE detector, which lies about 1300 km from Fermilab, will measure the neutrinos that are generated by Fermilab’s accelerator complex, which is just outside Chicago.

In a statement, Holtkamp said he is “deeply honoured” to lead the lab. “Fermilab has done so much to advance our collective understanding of the fundamentals of our universe,” he says. “I am committed to ensuring the laboratory remains the neutrino capital of the world, and the safe and successful completion of LBNF-DUNE is key to that goal. I’m excited to rejoin Fermilab at this pivotal moment to guide this project and our other important modernization efforts to prepare the lab for a bright future.”

Managerial experience

Fermilab has experienced a difficult few years, with questions raised about its internal management and external oversight. In August 2024 a group of anonymous self-styled whistleblowers published a 113-page “white paper” on the arXiv preprint server, asserting that the lab was “doomed without a management overhaul”.

Then in October that year, a new organization – Fermi Forward Discovery Group – was announced to manage the lab for the US Department of Energy. That move came under scrutiny given it is dominated by the University of Chicago and Universities Research Association (URA), a consortium of research universities, which had already been part of the management since 2007. Then a month later, almost 2.5% of Fermilab’s employees were laid off.

“We’re excited to welcome Norbert, who brings of a wealth of scientific and managerial experience to Fermilab,” noted University of Chicago president Paul Alivisatos, who is also chair of the board of directors of Fermi Forward Discovery Group.

Alivisatos thanked Kim for her “tireless service” as director. “[Kim] played a critical role in strengthening relationships with Fermilab’s leading stakeholders, driving the lab’s modernization efforts, and positioning Fermilab to amplify DOE’s broader goals in areas like quantum science and AI,” added Alivisatos.

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CERN accepts $1bn in private cash towards Future Circular Collider

Michael Banks — Mon, 19 Jan 2026 13:00:02 +0000

The CERN particle-physics lab near Geneva has received $1bn from private donors towards the construction of the Future Circular Collider (FCC). The cash marks the first time in the lab’s 72-year history that individuals and philanthropic foundations have agreed to support a major CERN project. If built, the FCC would be the successor to the Large Hadron Collider (LHC), where the Higgs boson was discovered.

CERN originally released a four-volume conceptual design report for the FCC in early 2019, with more detail included in a three-volume feasibility study that came out last year. It calls for a giant tunnel some 90.7 km in circumference – roughly three times as long as the LHC – that would be built about 200 m underground on average.

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The FCC has been recommended as the preferred option for the next flagship collider at CERN in the ongoing process to update the European Strategy for Particle Physics, which will be passed over to the CERN Council in May 2026.If the plans are given the green light by CERN Council in 2028, construction on the FCC electron-positron machine, dubbed FCC-ee, would begin in 2030. It would start operations in 2047, a few years after the High Luminosity LHC (HL-LHC) closes down, and run for about 15 years until the early 2060s.

The FCC-ee would focus on creating a million Higgs particles in total to allow physicists to study its properties with an accuracy an order of magnitude better that possible with the LHC. The FCC feasibility study then calls for a hadron machine, dubbed FCC-hh, to replace the FCC-ee in the existing 91 km tunnel. It would be a “discovery machine”, smashing together protons at high energy – about 85 TeV – with the aim of creating new particles. If built, the FCC-hh will begin operation in 2073 and run to the end of the century.

The funding model for the FCC-ee, which is expected to have a price tag of about $18bn, is still a work in progress. But it is estimated that at least two-thirds of the construction costs will come from CERN’s 24 member states with the rest needing to be found elsewhere. One option to plug that gap is private donations and in late December CERN received a significant boost from several organizations including the Breakthrough Prize Foundation, the Eric and Wendy Schmidt Fund for Strategic Innovation, and the entrepreneurs John Elkann and Xavier Niel. Together, they pledged a total of $1bn towards the FCC-ee.

Costas Fountas, president of the CERN Council, says CERN is “extremely grateful” for the interest. “This once again demonstrates CERN’s relevance and positive impact on society, and the strong interest in CERN’s future that exists well beyond our own particle physics community,” he notes.

Eric Schmidt, who founded Google, claims that he and Wendy Schmidt were “inspired by the ambition of this project and by what it could mean for the future of humanity”. The FCC, he believes, is an instrument that “could push the boundaries of human knowledge and deepen our understanding of the fundamental laws of the Universe” and could lead to technologies that could benefit society “in profound ways” from medicine to computing to sustainable energy.

The cash promised has been welcomed by outgoing CERN director-general Fabiola Gianotti. “It’s the first time in history that private donors wish to partner with CERN to build an extraordinary research instrument that will allow humanity to take major steps forward in our understanding of fundamental physics and the universe,” she said. “I am profoundly grateful to them for their generosity, vision, and unwavering commitment to knowledge and exploration.”

Further boost

The cash comes a few months after the Circular Electron–Positron Collider (CEPC) – a rival collider to the FCC-ee that also involves building a huge 100 km tunnel to study the Higgs in unprecedented detail – was not considered for inclusion in China’s next five-year plan, which runs from 2026 to 2030. There has been much discussion in China about whether the CEPC is the right project for the country, with the collider facing criticism from particle physicist and Nobel laureate Chen-Ning Yang, before he died last year.

Wang Yifang of the Institute of High Energy Physics (IHEP) in Beijing says they will submit the CEPC for consideration again in 2030 unless FCC is officially approved before then. But for particle theorist John Ellis from Kings College London, China’s decision to effectively put the CEPC on the back burner “certainly simplifies the FCC discussion”. “However, an opportunity for growing the world particle physics community has been lost, or at least deferred [by the decision],” Ellis told Physics World.

Ellis adds, however, that he would welcome China’s participation in the FCC. “Their accelerator and detector [technical design reviews] show that they could bring a lot to the table, if the political obstacles can be overcome,” he says.

However, if the FCC-ee goes ahead China could perhaps make significant “in-kind” contributions rather like those that occur with the ITER experimental fusion reactor, which is currently being built in France. In this case, instead of cash payments, the countries provide components, equipment and other materials.

Those considerations and more will now fall to the British physicist Mark Thomson, who took over from Gianotti as CERN director-general on 1 January for a five-year term. As well as working on funding requirements for the FCC-ee, top of his in-tray will actually be shutting down the LHC in June to make way for further work on the HL-LHC, which involves installing powerful new superconducting magnets and improving the detection.

About 90% of the 27 km LHC accelerator will be affected by the upgrade with a major part being to replace the magnets in the final focus systems of the two large experiments, ATLAS and CMS. These magnets will take the incoming beams and then focus them down to less than 10 µm in cross section. The upgrade includes the installation of brand new state-of-the-art niobium-tin (Nb₃Sn) superconducting focusing magnets.

The HL-LHC will probably not turn on until 2030, at which time Thomson’s term will nearly be over, but that doesn’t deter him from leading the world’s foremost particle-physics lab. “It’s an incredibly exciting project,” Thomson told the Guardian. “It’s more interesting than just sitting here with the machine hammering away.”

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+ Gamma Knife radiosurgery brings precision treatment to benign brain conditions + https://physicsworld.com/a/gamma-knife-radiosurgery-brings-precision-treatment-to-benign-brain-conditions/ + Thu, 27 Aug 2026 13:02:41 +0000 + + + + + https://physicsworld.com/?p=130101 + This podcast features Katharine Hunt of the Sheffield Teaching Hospitals NHS Foundation Trust

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Polarization-sensitive photoacoustic microscopy reveals heart tissue health

Tami Freeman — Mon, 19 Jan 2026 09:30:58 +0000

Imaging tissue fibrosis (a) Mid-infrared dichroism-sensitive photoacoustic microscopy (MIR-DS-PAM) images of cell-induced fibrosis (CIF) and normal control (NC) tissue; (c) MIR-DS-PAM images of drug-induced fibrosis (DIF) and NC tissue; (b) and (d) show the corresponding confocal fluorescence microscopy (CFM) images. Scale bars: 500 µm. (Courtesy: CC-BY 4.0/Light Sci. Appl. 10.1038/s41377-025-02117-0)

Many of the tissues in the human body rely upon highly organized microstructures to function effectively. If the collagen fibres in heart muscle become disordered, for instance, this can lead to or reflect disorders such as fibrosis and cancer. To image and analyse such structural changes, researchers at Pohang University of Science and Technology (POSTECH) in Korea have developed a new label-free microscopy technique and demonstrated its use in engineered heart tissue.

The ability to assess the alignment of microstructures such as protein fibres within tissue’s extracellular matrix provides a valuable tool for diagnosing disease, monitoring therapy response and evaluating tissue engineering models. Currently, however, this is achieved using histological imaging methods based on immunofluorescent staining, which can be labour-intensive and sensitive to the imaging conditions and antibodies used.

Instead, a team headed up by Chulhong Kim and Jinah Jang is investigating photoacoustic microscopy (PAM), a label-free imaging modality that relies on light absorption by endogenous tissue chromophores to reveal structural and functional information. In particular, PAM with mid-infrared (MIR) incident light provides bond-selective, high-contrast imaging of proteins, lipids and carbohydrates. The researchers also incorporated dichroism-sensitive (DS) functionality, resulting in a technique referred to as MIR-DS-PAM.

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“Dichroism-sensitivity enables the quantitative assessment of fibre alignment by detecting the polarization-dependent absorption of anisotropic materials like collagen,” explains first author Eunwoo Park. “This adds a new contrast mechanism to conventional photoacoustic imaging, allowing simultaneous visualization of molecular content and microstructural organization without any labelling.”

Park and colleagues constructed a MIR-DS-PAM system using a pulsed quantum cascade laser as the light source. They tuned the laser to a centre wavelength of 6.0 µm to correspond with an absorption peak from the C=O stretching vibration in proteins. The laser beam was linearly polarized, modulated by a half-wave plate and used to illuminate the target tissue.

Tissue analysis

To validate the functionality of their MIR-DS-PAM technique, the researchers used it to image a formalin-fixed section of engineered heart tissue (EHT). They obtained images at four incident angles and used the acquired photoacoustic data to calculate the photoacoustic amplitude, which visualizes the protein content, as well as the degree of linear dichroism (DoLD) and the orientation angle of linear dichroism (AoLD), which reveal the extracellular matrix alignment.

“Cardiac tissue features highly aligned extracellular matrix with complex fibre orientation and layered architecture, which are critical to its mechanical and electrical function,” Park explains. “These properties make it an ideal model for demonstrating the ability of MIR-DS-PAM to detect physiologically relevant histostructural and fibrosis-related changes.”

The researchers also used MIR-DS-PAM to quantify the structural integrity of EHT during development, using specimens cultured for one to five days before fixing. Analysis of the label-free images revealed that as the tissue matured, the DoLD gradually increased, while the standard deviation of the AoLD decreased – indicating increased protein accumulation with more uniform fibre alignment over time. They note that these results agree with those from immunofluorescence-stained confocal fluorescence microscopy.

Next, they examined diseased EHT with two types of fibrosis: cell-induced fibrosis (CIF) and drug-induced fibrosis (DIF). In the CIF sample, the average photoacoustic amplitude and AoLD uniformity were both lower than found in normal EHT, indicating reduced protein density and disrupted fibre alignment. DIF exhibited a higher photoacoustic amplitude and lower AoLD uniformity than normal EHT, suggesting extensive extracellular matrix accumulation with disorganized orientation.

Both CIF and DIF showed a slight reduction in DoLD, again signifying a disorganized tissue structure, a common hallmark of fibrosis. The two fibrosis types, however, exhibited diverse biochemical profiles and different levels of mechanical dysfunction. The findings demonstrate the ability of MIR-DS-PAM to distinguish diseased from healthy tissue and identify different types of fibrosis. The researchers also imaged a tissue assembly containing both normal and fibrotic EHT to show that MIR-DS-PAM can capture features in a composite sample.

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They conclude that MIR-DS-PAM enables label-free monitoring of both tissue development and fibrotic remodelling. As such, the technique shows potential for use within tissue engineering research, as well as providing a diagnostic tool for assessing tissue fibrosis or remodelling in biopsied samples. “Its ability to visualize both biochemical composition and structural alignment could aid in identifying pathological changes in cardiological, musculoskeletal or ocular tissues,” says Park.

“We are currently expanding the application of MIR-DS-PAM to disease contexts where extracellular matrix remodelling plays a central role,” he adds. “Our goal is to identify label-free histological biomarkers that capture both molecular and structural signatures of fibrosis and degeneration, enabling multiparametric analysis in pathological conditions.”

The researchers describe their microscopy technique in Light: Science & Applications.

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+ X-ray camera catches spin waves in the act + https://physicsworld.com/a/x-ray-camera-catches-spin-waves-in-the-act/ + Thu, 27 Aug 2026 07:53:22 +0000 + + + + + https://physicsworld.com/?p=130075 + Magnon microscope focuses on useful non-linear interactions

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Astronomer Daniel Jaffe named president of the Giant Magellan Telescope project

Michael Banks — Fri, 16 Jan 2026 15:30:52 +0000

Jaffe joins the Giant Magellan Telescope Corporation as it aims to secure the funding necessary to complete the $2.5bn telescope. (Courtesy: Giant Magellan Telescope – GMTO Corporation)

Astronomer Daniel Jaffe has been appointed the next president of the Giant Magellan Telescope Corporation – the international consortium building the $2.5bn Giant Magellan Telescope (GMT). He succeeds Robert Shelton, who announced his retirement last year after eight years in the role.

A former head of astronomy at the University of Texas at Austin from 2011 to 2015, Jaffe became vice-president for research at the university from 2016 to 2025 and he also served as interim provost from 2020 to 2021.

Jaffe has sat on the board of directors of the Association of Universities for Research in Astronomy and the Gemini Observatory and played a role in establishing the University of Texas at Austin’s partnership in the GMT.

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Under construction in Chile and expected to be complete in the 2030s, the GMT consists of seven mirrors to create a 25.4 m telescope. From the ground it will produce images 4–16 times sharper than the James Webb Space Telescope and will investigate the origins of the chemical elements, and search for signs of life on distant planets.

“I am honoured to lead the GMT at this exciting stage,” notes Jaffe. “[It] represents a profound leap in our ability to explore the universe and employ a host of new technologies to make fundamental discoveries.”

“[Jaffe] brings decades of leadership in research, astronomy instrumentation, public-private partnerships, and academia,” noted Taft Armandroff, board chair of the GMTO Corporation. “His deep understanding of the Giant Magellan Telescope, combined with his experience leading large research enterprises and cultivating a collaborative environment, make him exceptionally well suited to lead the observatory through its next phase of construction and toward operations.”

Jaffe joins the GMT at a pivotal time, as it aims to secure the funding necessary to complete the telescope with just over $1bn from private funds having been pledges so far. The collaboration recently added Northwestern University and the Massachusetts Institute of Technology to its international consortium taking the number of members to 16 universities and research institutions.

In June 2025 the GMT, which is already 40% completed, received NSF approval confirming that the observatory will advance into its “major facilities final design phase”, one of the final steps before becoming eligible for federal construction funding.

Yet it faces competition from another next-generation telescope – the Thirty Meter Telescope (TMT) that will use a segmented primary mirror consisting of 492 elements of zero-expansion glass for a 30 m-diameter primary mirror.

The TMT team chose Hawaii’s Mauna Kea peak as its location. However, protests by indigenous Hawaiians, who regard the site as sacred, have delayed the start of construction with officials identifying the island of La Palma, belonging to Spain’s Canary Islands, as an alternative site in 2019.

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+ Physics-based simulations could improve earthquake-damage predictions, why aren’t they being used? + https://physicsworld.com/a/physics-based-simulations-could-improve-earthquake-damage-predictions-why-arent-they-being-used/ + Wed, 26 Aug 2026 15:06:00 +0000 + + + + https://physicsworld.com/?p=130082 + Discussion and debate at the US National Conference on Earthquake Engineering

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India turns to small modular nuclear reactors to meet climate targets

No Author — Fri, 16 Jan 2026 12:30:55 +0000

India has been involved in nuclear energy and power for decades, but now the country is turning to small modular nuclear reactors (SMRs) as part of a new, long-term push towards nuclear and renewable energy. In December 2025 the country’s parliament passed a bill that allows private companies for the first time to participate in India’s nuclear programme, which could see them involved in generating power, operating plants and making equipment.

Some commentators are unconvinced that the move will be enough to help meet India’s climate pledge to achieving 500 GW of non-fossil-fuel based energy generation by 2030. Interestingly, however, India has now joined other nations, such as Russia and China, in taking an interest in SMRs. They could help stem the overall decline in nuclear power, which now accounts for just 9% of electricity generated around the world – down from 17.5% in 1996.

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Last year India’s finance minister Nirmala Sitharaman announced a nuclear energy mission funded with 200 billion Indian rupees ($2.2bn) to develop at least five indigenously designed and operational SMRs by 2033. Unlike huge, conventional nuclear plants, such as pressurized heavy-water reactors (PHWRs), most or all components of an SMR are manufactured in factories before being assembled at the reactor site.

SMRs, typically generate less than 300 MW of electrical power but – being modular – additional capacity can be brought on quickly and easily given their lower capital costs, shorter construction times, ability to work with lower-capacity grids and lower carbon emissions. Despite their promise, there are only two fully operating SMRs in the world – both in Russia – although two further high-temperature gas-cooled SMRs are currently being built in China. In June 2025 Rolls-Royce SMR was selected as the preferred bidder by Great British Nuclear to build the UK’s first fleet of SMRs, with plans to provide 470 MW of low-carbon electricity.

Cost benefit analysis

An official at the Department of Atomic Energy told Physics World that part of that mix of five new SMRs in India could be the 200 MW Bharat small modular reactor, which are based on pressurized water reactor technology and use slightly enriched uranium as a fuel. Other options are 55 MW small modular reactors and the Indian government also plans to partner with the private sector to deploy 220 MW Bharat small reactors.

Despite such moves, some are unconvinced that small nuclear reactors could help India scale its nuclear ambitions. “SMRs are still to demonstrate that they can supply electricity at scale,” says Karthik Ganesan, a fellow and director of partnerships at the Council on Energy, Environment and Water (CEEW), a non-profit policy research think-tank based in New Delhi. “SMRs are a great option for captive consumption, where large investment that will take time to start generating is at a premium.”

Ganesan, however, says it is too early to comment on the commercial viability of SMRs as cost reductions from SMRs depend on how much of the technology is produced in a factory and in what quantities. “We are yet to get to that point and any test reactors deployed would certainly not be the ones to benchmark their long-term competitiveness,” he says. “[But] even at a higher tariff, SMRs will still have a use case for industrial consumers who want certainty in long-term tariffs and reliable continuous supply in a world where carbon dioxide emissions will be much smaller than what we see from the power sector today.”

M V Ramana from the University of British Columbia, Vancouver, who works in international security and energy supply, is concerned over the cost efficiency of SMRs compared to their traditional counterparts. “Larger reactors are cheaper on a per-megawatt basis because their material and work requirements do not scale linearly with power capacity,” says Ramana. This, according to Ramana, means that the electricity SMRs produce will be more expensive than nuclear energy from large reactors, which are already far more expensive than renewables such as solar and wind energy.

Clean or unclean?

Even if SMRs take over from PHWRs, there is still the question of what do with its nuclear waste. As Ramana points out, all activities linked to the nuclear fuel chain – from mining uranium to dealing with the radioactive wastes produced – have significant health and environmental impacts. “The nuclear fuel chain is polluting, albeit in a different way from that of fossil fuels,” he says, adding that those pollutants remain hazardous for hundreds of thousands of years. “There is no demonstrated solution to managing these radioactive wastes – nor can there be, given the challenge of trying to ensure that these materials do not come into contact with living beings,” says Ramana.

Ganesan, however, thinks that nuclear energy is still clean as it produces electricity with much a lower environmental footprint especially when it comes to so-called “criteria pollutants”: ozone; particulate matter; carbon monoxide; lead; sulphur dioxide; and nitrogen dioxide. While nuclear waste still needs to be managed, Ganesan says the associated costs are already included in the price of setting up a reactor. “In due course, with technological development, the burn up will significantly higher and waste generated a lot lesser.”

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+ US orders universities to audit foreign research ties + https://physicsworld.com/a/us-orders-universities-to-audit-foreign-research-ties/ + Wed, 26 Aug 2026 13:11:21 +0000 + + + + https://physicsworld.com/?p=130060 + Move by the US Department of Defense affects 30 research universities

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Gravitational lensing sheds new light on Hubble constant controversy

Isabelle Dumé — Fri, 16 Jan 2026 10:00:13 +0000

Packed with physics This photo montage of the 12 August 2026 solar eclipse as seen from the Isle of Wight, UK, holds a surprising amount of science. (Courtesy: Sean Ryan)

The UK’s hot, dry summer provided widespread clear skies for the solar eclipse that took place on Wednesday 12 August 2026. It was not a total eclipse – you had to be in northern Spain for that – but Britain still enjoyed a partial eclipse between around 6 p.m. and 8 p.m. BST, depending on location.

With typically more than 90% of the Sun’s disc covered – and with the event occurring after many people had finished work – the circumstances were ideal for a rare, immersive mass-engagement with physics.

Many people had got hold of eclipse glasses in advance or searched through kitchen cupboards for a colander to produce shadow patterns
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Widespread public-awareness raising by professional and amateur astronomical societies had led to a strong build-up to the event in mainstream and social media. As a result, much of the public was aware the eclipse was coming, and many people had got hold of eclipse glasses in advance or, failing that, searched through kitchen cupboards for a colander to produce shadow patterns.

Here in the UK, friends and families gathered on west-facing hills, parks and village greens that evening with folding chairs, smartphones, cameras, telescopes and colanders, to enjoy the spectacle over a picnic tea. In built-up areas of towns and cities, many sought out west-facing windows of homes and offices.

I’m an old-school visual observer and recorded the eclipse sequence using 20-year-old equipment
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While the eclipse on the UK mainland was deepest in Cornwall, I took my chances on the Isle of Wight, just off the coast of southern England.

Amateur astrophotography has been revolutionized over the last few years thanks to specialized high-sensitivity astronomical CMOS cameras, but I’m an old-school visual observer and recorded the eclipse sequence using 20-year-old equipment.

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The montage presented here contains 36 frames spanning the entire eclipse sequence and packs in a wealth of physics. Besides the obvious relative motion of the Earth, Moon and Sun, three sunspot groups are visible, approximately delineating the solar equator; the camera was aligned with the sunspot groups and the equatorial mount maintained this orientation.

The Moon’s sharp-edged silhouette is a reminder that it has no atmosphere, whereas the Sun is brighter in the centre than the edge. Known as “limb-darkening”, it arises because of the temperature gradient of the tenuous solar photosphere – and is a reminder that the perceived edge of the Sun is merely a wavelength-dependent opacity transition.

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While we often describe the Sun as yellow, the transmission profile with the OD5 solar filter that I used here gives it a slightly silvery-blue tinge. But as the Sun sank lower in the sky during the evening, wavelength-dependent extinction and scattering reddened the light, so the silvery disc progressively turns distinctly yellow and then orange.

Along with the colour change, the solar disc takes on an oblate form in the final row of frames due to differential atmospheric refraction close to the horizon. Terrestrial clouds close to the local horizon are seen in the final frame.

For many people viewing an eclipse for the first time, talk of intersecting orbital planes is perhaps already too much physics for one evening, but for those who wish to look a little deeper, more questions – and more physics – pop up the closer you look. What have you spotted in the montage that I haven’t?

The technical stuff

I took these images using a portable 90 mm diameter Maksutov-Cassegrain telescope (a Meade ETX-90) on an equatorial mount with a battery-powered drive, a full-aperture glass OD5 solar filter, and a 25 mm focal-length eyepiece paired in eyepiece-projection mode with a 5 megapixel Sony Cyber-shot CCD digital camera.

The camera was set for manual operation: minimum ISO (100), minimum aperture (f/5.6), fixed focus (achieved at f/2.8), and manually adjusted exposure time (1/400 – 1/13 s). Image processing was minimal, conducted using ImageJ software, which is widely used in biomedical imaging.

Shadowing of the sensor by dust on the lens surfaces was partially corrected by dividing through by a normalized clear-sky exposure. Frames were cropped manually and re-scaled in intensity to compensate for increasing atmospheric absorption as the Sun sank towards the horizon, and for changes of exposure duration.

The post The 12 August 2026 partial solar eclipse as seen from the Isle of Wight appeared first on Physics World.

RFID-tagged drug capsule lets doctors know when it has been swallowed

Tami Freeman — Thu, 15 Jan 2026 09:15:21 +0000

Taking medication as and when prescribed is crucial for it to have the desired effect. But nearly half of people with chronic conditions don’t adhere to their medication regimes, a serious problem that leads to preventable deaths, drug resistance and increased healthcare costs. So how can medical professionals ensure that patients are taking their medicine as prescribed?

A team at Massachusetts Institute of Technology (MIT) has come up with a solution: a drug capsule containing an RFID tag that uses radiofrequency (RF) signals to communicate that it has been swallowed, and then bioresorbs into the body.

“Medication non-adherence remains a major cause of preventable morbidity and cost, but existing ingestible tracking systems rely on non-degradable electronics,” explains project leader Giovanni Traverso. “Our motivation was to create a passive, battery-free adherence sensor that confirms ingestion while fully biodegrading, avoiding long-term safety and environmental concerns associated with persistent electronic devices.”

The device – named SAFARI (smart adherence via Faraday cage and resorbable ingestible) – incorporates an RFID tag with a zinc foil RF antenna and an RF chip, as well as the drug payload, inside an ingestible gelatin capsule. The capsule is coated with a mixture of cellulose and molybdenum particles, which blocks the transit of any RF signals.

SAFARI capsules Photos of the capsules with (left) and without (right) the RF-blocking coating. (Courtesy: Mehmet Say)

Once swallowed, however, this shielding layer breaks down in the stomach. The RFID tag (which can be preprogrammed with information such as dose metadata, manufacturing details and unique ID) can then be wirelessly queried by an external reader and return a signal from inside the body confirming that the medication has been ingested.

The capsule itself dissolves upon exposure to digestive fluids, releasing the desired medication; the metal antenna components also dissolve completely in the stomach. The use of biodegradable materials is key as it eliminates the need for device retrieval and minimizes the risk of gastrointestinal (GI) blockage. The tiny (0.16 mm²) RFID chip remains intact and should safely leave the body through the GI tract.

Traverso suggests that the first clinical applications for the SAFARI capsule will likely be high-risk settings in which objective ingestion confirmation is particularly valuable. “[This includes] tuberculosis, HIV, transplant immunosuppression or cardiovascular therapies, where missed doses can have serious clinical consequences,” he tells Physics World.

In vivo demonstration

To assess the degradation of the SAFARI capsule and its components in vitro, Traverso and colleagues placed the capsule into simulated gastric fluid at physiological temperature (37 °C). The RF shielding coating dissolved in 10–20 min, while the capsule and the zinc layer in the RFID tag disintegrated into pieces after one day.

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Next, the team endoscopically delivered the SAFARI capsules into the stomachs of sedated pigs, chosen as they have a similar sized GI tract to humans. Once in contact with gastric fluid in the stomach, the capsule coating swelled and then partially dissolved (as seen using endoscopic images), exposing the RFID tag. The researchers found that, in general, the tag and capsule parts disintegrated in the stomach at up to 24 h later.

A panel antenna positioned 10 cm from the animal captured the tag data. Even with the RFID tags immersed in gastric fluid, the external receiver could effectively record signals in the frequency range of 900–925 MHz, with RSSI (received signal strength indicator) values ranging from 65 to 78 dB – demonstrating that the tag could effectively transmit RF signals from inside the stomach.

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The researchers conclude that this successful use of SAFARI in swine indicates the potential for translation to clinical research. They note that the device should be safe for human ingestion as its composite materials meet established dietary and biomedical exposure limits, with levels of zinc and molybdenum orders of magnitude below those associated with toxicity.

“We have demonstrated robust performance and safety in large-animal models, which is an important translational milestone,” explains first author Mehmet Girayhan Say. “Before human studies, further work is needed on chronic exposure with characterization of any material accumulation upon repeated dosing, as well as user-centred integration of external readers to support real-world clinical workflows.”

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Quantum state teleported between quantum dots at telecoms wavelengths

Isabelle Dumé — Wed, 14 Jan 2026 16:00:47 +0000

A radiation shielding vest tested during the uncrewed Artemis I flight in 2022 has been shown to significantly reduce the radiation dose that future astronauts or deep-space tourists might receive.

The data for this analysis were obtained via seating two human-tissue-equivalent female torso phantoms in the Orion crew capsule. While the “Zohar” phantom wore the new AstroRad vest, its travel companion “Helga” did not. Numerous radiation dosimeters placed in and on the phantoms allowed the received radiation dose to be compared.

“Exposure to radiation in space is unavoidable, and a single major solar particle event (SPE) can deliver more than one-third of NASA’s 600 millisievert career effective-dose limit. A three-year round trip to Mars would equal or exceed the career limit, which corresponds to a 3% mortality risk from radiation-induced cancer. So we developed the AstroRad vest to significantly reduce this hazard,” explains immunologist Oren Milstein, CEO of StemRad Radiation Protection, which began developing the vest with Lockheed Martin in 2015.

Dosimetry phantoms The Helga and Zohar (wearing the AstroRad vest) phantoms inside the Orion spacecraft at the NASA Vehicle Assembly Building prior to the launch of Artemis I. (Courtesy: NASA/Lockheed Martin/DLR)

The shielding thickness varies throughout the garment according to the radiation sensitivity of the underlying organs, with breasts, colon, lungs, ovaries, stomach and red bone marrow having concentrated shielding in the test vest. Milstein was inspired to develop this targeted architecture based on the experiences of his PhD supervisor, who treated the first responders to the 1986 Chernobyl nuclear power plant disaster.

With damage to bone marrow the accepted cause of death for all those emergency workers who lost their lives within months of the accident, “that heritage instilled in me a desire to protect people from radiation by selective shielding of the bone marrow,” Milstein explains, adding that the female focus of this experiment is because women have a higher predicted risk of radiation-induced cancer than men.

Astronauts currently shield from SPEs in “storm shelters” consisting of barricades of supplies, or by moving into areas containing more hardware against the walls. AstroRad provides a similar level of protection to the most robust shelter configuration while also “allowing the astronaut wearing it to move around the cabin and continue mission-critical tasks,” radiation physicist Jordan Houri, lead scientist for space exploration at StemRad, tells Physics World.

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To maintain flexibility, the vest is constructed from thousands of hexagonal tessellated rods of high-density polyethylene (HDPE) sandwiched between two layers of elastic fabric. The shielding components can also slide past one another and stretch. HDPE was chosen for its high proportion of hydrogen – which is extremely effective at shielding against charged particle space radiation.

While Artemis I did not encounter a solar storm, Orion traversed the inner Van Allen belt, whose protons cover a similar energy range to those in SPEs. This enabled the team to construct a Monte Carlo model of the experiment for testing different radiation environments.

“We created digital twins of Helga and Zohar, the AstroRad vest, radiation detectors and spacecraft shielding,” explains Houri. “Using this model, we generated hundreds of billions of virtual protons and electrons representing the radiation environment of the inner Van Allen belt, before comparing the predicted detector responses directly with the measurements recorded during Artemis I.”

With close agreement found, the researchers then simulated measured SPEs from August 1972 and October 1989. As detailed in their recent Science Advances paper, this revealed that wearing AstroRad would reduce effective dose by around 60% in an August 1972-type scenario, and by almost 40% for a 1989-type SPE – sparing astronauts the dose equivalent from up to 193 and 131 days of deep space travel, respectively.

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Combining these results with those from previous experiments, which tested the vests’ ergonomics on the International Space Station, is allowing the researchers to improve comfort and ease of motion, and reduce mass. They are also exploring whether lighter, empty vests could be filled with recycled polyethylene after launch.

Alongside the health benefits, reducing radiation exposure makes economic sense as it extends astronauts’ careers, concludes Milstein, who hopes that the AstroRad vests can help “make lunar habitation and Mars travel truly sustainable and not just a dream”.

The post Radiation shielding vest could reduce cancer risk for astronauts on deep space missions appeared first on Physics World.

Quantum metrology at NPL: we explore the challenges and opportunities

Hamish Johnston — Wed, 14 Jan 2026 14:02:04 +0000

This episode of the Physics World Weekly podcast features a conversation with Tim Prior and John Devaney of the National Physical Laboratory (NPL), which is the UK’s national metrology institute.

Prior is NPL’s quantum programme manager and Devaney is its quantum standards manager. They talk about NPL’s central role in the recent launch of NMI-Q, which brings together some of the world’s leading national metrology institutes to accelerate the development and adoption of quantum technologies.

Prior and Devaney describe the challenges and opportunities of developing metrology and standards for rapidly evolving technologies including quantum sensors, quantum computing and quantum cryptography. They talk about the importance of NPL’s collaborations with industry and academia and explore the diverse career opportunities for physicists at NPL. Prior and Devaney also talk about their own careers and share their enthusiasm for working in the cutting-edge and fast-paced field of quantum metrology.

This podcast is sponsored by the National Physical Laboratory.

Mapping electron phases in nanotube arrays

Lorna Brigham — Wed, 14 Jan 2026 12:56:38 +0000

Quantum dot LEDs (QLEDs) are of interest because they emit bright light with highly pure colours, making them attractive for display and lighting applications. They also have the potential to be manufactured at lower cost using solution-processing techniques. However, producing high-performance QLEDs remains challenging because the quantum dots must be uniformly distributed within a densely packed film. Poor film uniformity can lead to lower efficiency and faster device degradation.

In this study, machine learning was used to identify solvent conditions that produce the most uniform quantum dot films. Several solvents were characterised using five key solvent parameters that influence how quantum dots arrange themselves as the solvent evaporates. Film uniformity was assessed using atomic force microscopy, which provides detailed information about surface morphology and roughness.

Three machine learning models were trained to predict film uniformity from the solvent properties. Support Vector Regression was found to provide the most accurate predictions and was subsequently used to identify an optimal mixed-solvent formulation. Grazing-Incidence Small-Angle X-ray Scattering confirmed that the resulting films exhibited more homogeneous quantum dot packing.

The optimised solvent formulation produced QLEDs with higher efficiency and longer operational lifetimes than devices fabricated using single solvents. Overall, the study demonstrates that film homogeneity is a critical factor in QLED performance and highlights the potential of machine learning as a powerful tool for optimising solution-processed optoelectronic devices.

Read the full article

Dimensionality and correlation effects in coupled carbon nanotube arrays

Xiaosong Deng et al 2025 Rep. Prog. Phys. 88 088001

Machine-learning-enabled solvent engineering for uniform quantum dot packing in efficient and stable quantum-dot light-emitting diodes

Beomsoo Chun et al 2026 Rep. Prog. Phys. 89 078002

Do you want to learn more about this topic?

Structural approach to charge density waves in low-dimensional systems: electronic instability and chemical bonding Jean-Paul Pouget and Enric Canadell (2024)

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Materials, photophysics and device engineering of perovskite light-emitting diodes by Ziming Chen et al. (2021)

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Quantum computers may pay a price for keeping time

Paul Mabey — Wed, 26 Aug 2026 06:58:53 +0000

Most quantum computers today do not work in isolation. They rely on carefully timed signals from classical electronics, lasers or magnetic fields to tell the qubits when to perform each operation.

In ordinary quantum-computing theory, the qubits are treated as the computer while these timing signals are treated as external infrastructure. When calculating the energy required to run a quantum computer, drawing a boundary around the qubits like this will inevitably hide part of the real-world energy cost. Draw the boundary around the whole computing machine, including its clock, and a new energetic cost appears.

This is the idea behind new research from a team of researchers from Austria. In a new study, they introduced the idea of an autonomous quantum processing unit (aQPU). The aQPU has four main parts: a memory where the calculation happens, an instruction register that stores the program, a tick register that counts the steps, and an internal quantum clock that drives the whole process. The idea is similar to a mechanical machine that, once started, runs without an external operator.

The team showed there is an inescapable trade-off between accuracy and thermodynamics. If the clock ticks at slightly uncertain times, the quantum gates are applied imperfectly, reducing the fidelity of the computation. The authors found that the error grows with the length of the program and shrinks as the clock becomes more accurate. But more accurate clocks generally dissipate more entropy, meaning they produce more thermodynamic irreversibility.

In practice, such entropy production is usually associated with dissipated energy, often as heat. For quantum computers, this is especially awkward because many platforms already need delicate cooling and isolation procedures.

The new study does not propose a practical computer yet. Instead it gives physicists a cleaner way to ask how much energy quantum computation fundamentally requires. Even when quantum gates are mathematically reversible, the physical act of controlling them with sufficient precision may not be thermodynamically free.

Read the full article

Autonomous quantum processing unit: an autonomous thermal computing machine & its physical limitations – IOPscience

Florian Meier et al 2026 Rep. Prog. Phys. 89 077601

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CMS spots hints of a new form of top‑quark matter

Lorna Brigham — Wed, 14 Jan 2026 12:54:38 +0000

Wireless power transfer systems are used to transfer electricity without a physical cable, for example in wireless electric vehicle charging, medical implants and consumer electronics such as smartwatches. In real systems, poor alignment and variable distances can reduce efficiency, causing some of the transmitted energy to be reflected back towards its source rather than being absorbed by the receiver.

Wireless power transfer research tends to focus on engineering solutions such as improved coil designs, impedance matching and frequency tuning. However, in this work, the researchers investigate a more fundamental question: how can the physics of time-domain wave interference be used to control energy flow within resonant systems?

A phenomenon known as Coherent Perfect Absorption occurs when a system completely absorbs incoming energy with negligible reflection. However, this requires specific conditions and a system that is perfectly matched, operating at a point of equilibrium known as the steady state. Here, the researchers report a new effect called Transient Coherent Perfect Absorption. Rather than relying on a steady state, TCPA operates during the brief transition period immediately after a system is switched on.

During this transient period, a steady wave produced by the source coexists with a temporary, decaying wave created by energy stored within the system. These waves interfere with one another and both contribute to the reflected signal. When they are exactly out of phase, the reflected signals cancel out. As a result, a system that would normally reflect a significant amount of incoming energy can briefly behave as though it were perfectly matched, absorbing almost all of the incoming energy.

While this is fundamentally a physics study of wave behaviour and interference, it introduces a new way to suppress energy reflections in resonant systems. In the future, the approach could help improve the efficiency of wireless power transfer and other energy-delivery technologies by reducing losses under imperfect operating conditions.

Read the full article

Observation of a pseudoscalar excess at the top quark pair production threshold

The CMS Collaboration 2025 Rep. Prog. Phys. 88 087801

Transient coherent perfect absorption enables efficient wireless power transfer

Liang Hu et al 2026 Prog. Energy 8 024001

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The sea of quarks and antiquarks in the nucleon D F Geesaman and P E Reimer (2019)

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The rise of electric vehicles—2020 status and future expectations by Matteo Muratori et al. (2021)

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Photonics West explores the future of optical technologies

No Author — Wed, 14 Jan 2026 12:00:17 +0000

For particle physicists, bigger has always been better. The first working cyclotron, which was built by Ernest Lawrence in California in 1931, was little more than 35 cm in circumference and accelerated protons to 80 keV. Compare that with CERN’s Large Hadron Collider (LHC), which is more than 27 km long and has been creating protons with energies of 7 TeV per beam – some eight orders of magnitude higher.

Only recently, though, have the burgeoning energy requirements of ever-larger accelerator facilities become a cause for concern. It was not until 2020 that CERN published its first-ever environmental report, which outlined to the public how the lab was reducing its energy consumption. Thanks to innovations in cryogenics, for example, CERN reported that the “data per joule” doubled between the LHC’s first and second experimental runs.

All good and well. Yet while their core mission of fundamental scientific discovery remains paramount, it’s clear that – if nothing changes – the environmental impact of new and upgraded accelerator complexes will track in tandem with the size, energy footprint and resource consumption of these large-scale research facilities.

The numbers are eye-watering. Particle-accelerator research centres currently consume hundreds of gigawatt-hours (GWh) of electricity per year – roughly the energy budget of a mid-sized European city. CERN’s unique array of accelerators, detectors, computers and technical infrastructure, for example, together account for about 95% of the lab’s total electricity use of 1290 GWh in 2024, with the LHC alone soaking up 695 GWh.

What if bigger isn’t better?

It’s not a good look given the climate crisis – and only made worse with oil and gas prices soaring after the effective closure of the Strait of Hormuz. Fortunately, the accelerator-science community is ramping up efforts to make its core technologies and facilities more sustainable. The aim is not only to cut the energy and resources that accelerators use, but also to understand – and, more importantly, minimize – their “whole-lifetime” environmental impact.

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In fact, with CERN bringing the upgraded High Luminosity LHC online by 2030, mulling over a 91 km-circumference Future Circular Collider, and China eyeing up a 100 km collider of its own, now is a good time to embed environmental impact-reduction techniques into accelerator designs from the start.

That, at least, is the hope of a group of accelerator scientists and sustainability experts from the UK, Switzerland and Germany, who in June published a “living document” that puts environmental sustainability front-and-centre in the planning, construction, operation and decommissioning of large-scale accelerator facilities (EPJ Research Infrastructures 10 12).

“We’re seeing a surge in interest from colleagues across the accelerator community, all of them eager to incorporate environmental sustainability into their work and to share lessons learned,” says Hannah Wakeling, lead author of the report. An accelerator physicist in the John Adams Institute at the University of Oxford, UK, Wakeling’s own research involves measuring the carbon footprint of particle accelerators, their use of raw materials and even their wider impact on biodiversity.

Permanent waves The UK’s Zero Power Tuneable Optics (ZEPTO) project is developing tuneable permanent magnets for accelerator facilities as an energy-efficient alternative to resistive electromagnets. Here engineers are installing a ZEPTO magnet on the booster-to-storage-ring transfer line at the Diamond Light Source synchrotron facility in Oxfordshire. (Courtesy: Science and Technology Facilities Council)

Trouble is, measuring and improving the environmental sustainability of accelerator facilities is not easy. Labs often don’t have enough funding, staff or time for such initiatives. Sustainability recommendations are either too generic or cannot be applied to accelerator science and technology. There’s also uncertainty about how to incorporate environmental sustainability into day-to-day operations.

We hope that the guidelines will help accelerator facilities make informed decisions that balance scientific progress with environmental responsibility
+Hannah Wakeling, University of Oxford

Inspired by various initiatives in big science (see “Sustainable acceleration”, below), Wakeling and colleagues’ open-access resource has 110 practical sustainability recommendations for anyone building, planning or running accelerator facilities. It includes advice on procuring resources responsibly and reducing environmental impact through, for example, tunnelling, shielding, component design, waste management and green computing. There are also recommendations on skills, knowledge transfer and culture change, the latter being what the authors think will have most impact.

“Looking at accelerator programmes through the lens of sustainability gives us an opportunity to do things differently,” notes Wakeling. “We hope that the updated version of our high-level guidelines [v1.0 was published in 2025] will help accelerator facilities make informed decisions that balance scientific progress with environmental responsibility.”

Towards accelerator 2.0

In general, the biggest opportunity to make accelerators more sustainable is when they are still being designed and conceived. “At these crucial stages,” says Wakeling, “environmental impact assessments should be employed to highlight the areas of highest potential for impact reductions and more sustainable designs.”

What’s more, argues Wakeling, any decision to build or upgrade an accelerator shouldn’t depend just on its cost or scientific output but on how environmentally sustainable it will be too. That, in turn, means prioritizing R&D funding for enabling technologies that can make the most difference and co-ordinating efforts between large-scale facilities to avoid scientific duplication and to minimize the consumption of resources.

One relevant effort is a pan-European consortium called Research Facility 2.0 (RF 2.0), which is aiming to develop accelerator facilities that can run entirely on renewable energy – in effect, almost independently of the public power grid. A three-year, €5.6m initiative funded by the European Union’s Horizon programme and the Swiss State Secretariat for Education, Research and Innovation, RF 2.0 includes major accelerator labs like CERN, DESY and HZB (both in Germany), ALBA (Spain) and MAX IV (Sweden) plus the Karlsruhe Institute of Technology (KIT) and four high-tech SMEs.

Large-scale research infrastructures are a public good but they are inflexible and found wanting when it comes to environmental sustainability
+Giovanni De Carne, director of KIT’s Institute for Technical Physics

“We are addressing a couple of fundamental problems,” says RF 2.0 head Giovanni De Carne, who is director of KIT’s Institute for Technical Physics. One issue is purely economic: a particle accelerator consumes a lot of electrical energy and therefore accounts for a recurring chunk of operating expenditure. In “run” years, for example, electricity costs typically equate to 5–10% of CERN’s annual budget.

They’ve got the power RF 2.0 engineers from CERN and industry partner Zaphiro have installed 24 phasor measurement units to monitor disturbances in the Large Hadron Collider’s power network, including the BE1 400 kV switchyard (above), the main energy gateway to CERN. The demonstrator project aims to enhance the network’s resilience and energy-efficiency. (Courtesy: Nikolaos Sapountzoglu/CERN)

“The second problem is practical, but also philosophical,” De Carne adds. “Large-scale research infrastructures are a public good – driving scientific and societal impact – but they are inflexible and found wanting when it comes to environmental sustainability, consuming large amounts of raw materials during construction and regular operations.”

RF 2.0’s goal is therefore to analyse the many ways accelerators use energy – from components and systems to experiments and engineering – and to develop and test novel platform technologies in real-world settings. One notable RF 2.0 demonstrator project, for example, led to a redesign of permanent magnets that steer and focus beams at the MAX IV synchrotron, reducing energy use and heat losses by up to 40%.

Another involved retrofitting solid-state amplifiers with energy-efficient “active parameterization” controllers to enhance particle acceleration at the ALBA synchrotron; it yielded 18% energy savings in one year versus prior technologies. A parallel R&D track has also led to sustainable high-performance computing initiatives such as a summer energy-saving programme at DESY’s data centre, reducing the power draw during the hottest parts of the day.

Permanent attraction RF 2.0 partners have been exploring the long-term environmental and operational benefits of using permanent magnets (rather than electromagnets) in accelerator systems, including a demonstrator project in the storage ring of Spain’s ALBA synchrotron light source. Here the actual electromagnets are shown along with the electrical and cooling connections that won’t be needed with a permanent magnet solution. (Courtesy: ALBA)

Meanwhile at CERN, an RF 2.0 team has installed 24 phasor measurement units (PMUs) at the lab. These smart grid devices, which record the magnitude and timing of voltage/current fluctuations, are able to monitor harmonics, voltage sags and grid disturbances within the LHC’s power network.

By recording phenomena that would otherwise go unnoticed with traditional metering systems, the PMUs help engineers to implement counter-measures to make the accelerator grid more robust. In the first year of operation, the devices recorded 135 voltage sags and rapid voltage-change events, with 18 of these adversely impacting operation of the accelerator complex – mainly affecting magnets and radio-frequency (RF) acceleration schemes.

“RF 2.0 cannot work in one single direction – a multidisciplinary approach is key,” says De Carne. “We are bringing together physicists, engineers and technologists who, under normal circumstances, rarely talk to each other. The project provides a forum for them to connect and share insights on common problems but from their own unique perspective. It’s been a real game-changer.”

The RF 2.0 programme finishes at the end of 2026, after which De Carne hopes to secure follow-on EU funding for RF 2.0 to merge with another pan-European project called Innovate for Sustainable Accelerator Systems (iSAS). The two projects look like a neat fit, with iSAS consisting of 11 academic labs and six companies seeking to make superconducting RF cavities – a workhorse accelerator technology – more energy-efficient.

Sustainable acceleration

The following sustainability initiatives are a useful starting point for scientists and engineers who want to evaluate and lower the environmental impact of accelerator projects at an institutional, project or individual level.

Meet PicoQuant at BiOS booth #8511 and Photonics West booth #3511.
Sustainable HECAP+ is a group of researchers in high-energy physics, cosmology, astroparticle physics and beyond who are promoting environmentally sustainable practices in areas such as computing, energy, mobility, research infrastructure, resources and waste.
The ICFA Panel on Sustainable Accelerators and Colliders is promoting “energy-efficient and sustainable accelerator concepts, technologies and strategies…and the use of accelerators for the development of carbon-neutral energy sources”.
Flexibility in RIs for global CArbon Neutrality (FlexRICAN) is a pan-European academic-industry consortium evaluating how research facilities can enhance energy flexibility for the European electrical grid and contribute to local heating networks through waste heat recovery.
Europe-America-Japan Accelerator Development Exchange Programme (EAJADE) has a work package of sustainable technologies for accelerator facilities including high-efficiency superconducting RF cavities and RF amplifiers.
ErUM Data Hub is a German initiative helping 20,000 scientists exploring “the universe and matter” to make data management, software and digital tools more environmentally sustainable.
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Disruptive thinking, sustainable outcomes

Along another coordinate, there’s also top-down pressure for a more sustainable approach to future accelerators from the European Strategy Group for Particle Physics (ESG), which guides the future of the field in Europe. “Energy consumption and emissions must be minimized when realizing and operating facilities and projects,” is the ESG’s unequivocal message in the 2026 update to its third strategy paper. “The design of new particle physics infrastructures should be as sustainable as possible, balancing important sustainability aspects with cost and physics performance.”

The ESG argues that R&D funding should be allocated to platform technologies with the most potential to yield energy savings. These include systems that convert grid power to RF more efficiently for particle acceleration, with some studies suggesting it could be possible to quadruple the efficiency with which RF systems convert electrical power into radiant power. Other promising technologies include thin-film superconducting RF cavities operating at higher cryogenic temperatures (around 4.2 K or higher versus 2 K for bulk niobium cavities).

Also important are novel permanent and high-temperature superconducting magnets that minimize heat losses. “Comparing the carbon footprints of electromagnet and permanent-magnet quadrupoles,” says Wakeling in Oxford, “the higher manufacturing impact of a permanent magnet can, in certain cases, be offset by its lower operational impact in as little as one year. Worth noting as well that this conclusion only considers carbon and doesn’t compare other environmental impacts.”

Another sustainability pathway is the use of AI and machine-learning to optimize the efficiency of accelerator experiments – for example, by focusing on intersecting parameters tuned to improve equipment reliability, lifetime and resource consumption. In parallel, AI could cut the huge computational needs of particle physics by requiring fewer “events” to be stored and lowering computing time.

Longer term, researchers are prioritizing disruptive accelerator concepts that could slash the size, cost and carbon footprint of next-generation facilities. One example is the energy-recovery linac, in which superconducting RF cavities decelerate a “used” particle beam and recycle the kinetic energy to accelerate new particles to higher energies. Another is plasma-wakefield acceleration, which uses laser- or particle-beam-driven intense “plasma waves” as the accelerating medium, yielding electric fields up to 1000 times greater than in classical accelerators.

Innovate and accelerate Hannah Wakeling (left) from the University of Oxford is one physicist seeking to make accelerator programmes more sustainable. Giovanni De Carne (right), director of the Institute for Technical Physics at KIT in Germany, runs the European RF 2.0 programme, which aims to develop accelerator facilities that can run entirely on renewable energy. (Courtesy: John Adams Institute and KIT)

The best of all worlds

Notwithstanding all this technology innovation, so many factors influence accelerator design that the “best” decision in terms of its environmental benefits can’t always be made. “In the end,” says Wakeling, “this is all a balancing act: we want accelerator facilities to be cutting-edge in terms of their scientific output, but we also want them to be cutting-edge when it comes to environmental sustainability.”

As for next steps, Wakeling and co-authors now plan to assess the anticipated impact of their 110 recommendations – whether high, medium or low – and the potential difficulty of putting them into practice (by referencing technology-readiness level, for example). Work is also underway to incorporate more quantitative analyses, including target figures for selected recommendations based on case studies from the accelerator community.

Equally, when assessing an accelerator’s emissions over its whole life-cycle, Wakeling thinks there is much to learn from the space-science community, which has developed the Open-source Rocket and Constellation Lifecycle Emissions (ORACLE) GitHub repository. This initiative seeks to cut the carbon footprint of the space industry – especially large constellations of satellites – by allowing researchers to share code and data.

“We applaud efforts like ORACLE and wish to encourage and promote similar programmes within fields applicable to accelerator science,” says Wakeling. But it’s clear that significant research is still required to tackle the complex environmental challenges in accelerator science, with Wakeling and colleagues aiming to update their living document as new information and technologies become available.

“We invite contributions from colleagues within the accelerator community,” Wakeling concludes, “to ensure this resource remains relevant, comprehensive and impactful.”

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Mission to Mars: from biological barriers to ethical impediments

Sam Jarman — Wed, 14 Jan 2026 11:00:14 +0000

A voting system with a high level of security intrinsically guaranteed by quantum mechanics has been demonstrated by two independent teams – one led by Federico Centrone at the Barcelona Institute of Technology and the other led by Rob Thew at the University of Geneva.

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Their systems employ a quantum protocol that was first proposed by Centrone and colleagues in 2022 and uses a system of entangled qubits to ensure every voter has complete anonymity.

A conventional voting system – paper or electronic – could be hacked or corrupted at the counting stage, resulting in a rigged outcome or lack of anonymity. In 2007, Anne Broadbent and Alain Tapp at the University of Montreal proposed a possible solution: an e-voting protocol in which an election is broken into as many rounds as there are voters.

Before anyone casts a vote, Broadbent and Tapp’s system secretly assigns each participant to be the “real” voter in exactly one designated round. In that round, the chosen voter picks a value (either 0 or 1) representing their actual choice.

Secret ballot

In every other round, the system automatically submits a pre-assigned value on the voter’s behalf, engineered so the round’s total has a fixed parity – either always odd or always even. The real voter’s free choice then either flips this total to the opposite parity or leaves it unchanged, and the final odd or even result is recorded. Once every round is complete, each voter will have had their real say – but from the outside, the identity of the real voter in any given round is completely hidden.

Although this scheme is watertight in principle, there is still no guarantee that the e-voting system itself can be fully trusted. In 2022, a team led by Centrone proposed how this loophole could be closed by harnessing entanglement between quantum bits, or qubits.

In the quantum protocol, each voter is assigned a single qubit, prepared as part of one joint entangled state spanning all voters together. When measured, each qubit is randomly either a 0 or 1, But, because of the type of entanglement between the qubits, the total number of 1s across all voters is guaranteed to have the expected parity. Since not even the e-voting system itself can know the outcome of any individual measurement in advance, the protocol removes the need to trust whoever is distributing the values.

Easily adapted

Thew’s team realised that it could create this protocol in the lab. “We had just finished another experiment concerning distributed polarization entanglement and realized we could ‘easily’ adapt our setup to produce the entangled states required for the voting protocol,” says Geneva’s Joey Marcellino.

Both teams used spontaneous parametric down-conversion (SPDC) to create the entangled qubits, which were photons. Here, a laser is fired into a nonlinear crystal, splitting single photons into pairs of lower-energy photons that are entangled in terms of their polarization states.

SPDC is then repeated using the newly-entangled photons, chaining pairs together until reaching the same number of entangled photons as there are voters – albeit a small number in these demonstrations. The result is one single, large entangled state. Each individual photon then passes through a 50/50 beam splitter, is coupled into an optical fibre, and sent to a detector, where its state is measured.

Fidelity and success

In their first experimental tests of the technique, Centrone and colleagues were able to create the entanglement required for the voting protocol at success rate of about 96%. Meanwhile, Thew’s team achieved an 87% success rate.

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Commenting on his colleagues’ result, Marcellino says, “This suffices as a proof-of-principle for the protocol and our modified approach, although obviously we would want to improve these numbers significantly for real-world applications”.

For now, the result demonstrates that e-voting systems with quantum-guaranteed security are achievable, using existing technologies including single-photon sources, detectors, and entanglement generation schemes.

“Moreover, in the end the protocol is just a way to anonymously distribute a bit with perfect security,” Marcellino adds. “While this is obviously useful for voting, it could also work as an anonymous message board, or to enable anonymous distributed computation.”

The research is described in Physical Review Letters: Thew and colleagues; Centrone and colleagues.

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Researchers harness sunlight to generate quantum entanglement

No Author — Tue, 25 Aug 2026 08:00:10 +0000

“It’s hard to say when exactly sending people to Mars became a goal for humanity,” ponders author Scott Solomon in his new book Becoming Martian: How Living in Space Will Change Our Bodies and Minds – and I think we’d all agree. Ten years ago, I’m not sure any of us thought even returning to the Moon was seriously on the cards. Yet here we are, suddenly living in a second space age, where the first people to purchase one-way tickets to the Red Planet have likely already been born.

The technology required to ship humans to Mars, and the infrastructure required to keep them alive, is well constrained, at least in theory. One could write thousands of words discussing the technical details of reusable rocket boosters and underground architectures. However, Becoming Martian is not that book. Instead, it deals with the effect Martian life will have on the human body – both in the short term across a single lifetime; and in the long term, on evolutionary timescales.

This book’s strength lies in its authorship: it is not written by a physicist enthralled by the engineering challenge of Mars, nor by an astronomer predisposed to romanticizing space exploration. Instead, Solomon is a research biologist who teaches ecology, evolutionary biology and scientific communication at Rice University in Houston, Texas.

Becoming Martian starts with a whirlwind, stripped-down tour of Mars across mythology, astronomy, culture and modern exploration. This effectively sets out the core issue: Mars is fundamentally different from Earth, and life there is going to be very difficult. Solomon goes on to describe the effects of space travel and microgravity on humans that we know of so far: anaemia, muscle wastage, bone density loss and increased radiation exposure, to name just a few.

Where the book really excels, though, is when Solomon uses his understanding of evolutionary processes to extend these findings and conclude how Martian life would be different. For example, childbirth becomes a very risky business on a planet with about one-third of Earth’s gravity. The loss of bone density translates into increased pelvic fractures, and the muscle wastage into an inability for the uterus to contract strongly enough. The result? All Martian births will likely need to be C-sections.

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Solomon applies his expertise to the whole human body, including our “entourage” of micro-organisms. The indoor life of a Martian is likely to affect the immune system to the degree that contact with an Earthling would be immensely risky. “More than any other factor, the risk of disease transmission may be the wedge that drives the separation between people on the two planets,” he writes. “It will, perhaps inevitably, cause the people on Mars to truly become Martians.” Since many diseases are harboured or spread by animals, there is a compelling argument that Martians would be vegan and – a dealbreaker for some I imagine – unable to have any pets. So no dogs, no cats, no steak and chips on Mars.

Let’s get physical

The most fascinating part of the book for me is how Solomon repeatedly links the biological and psychological research with the more technical aspects of designing a mission to Mars. For example, the first exploratory teams should have odd numbers, to make decisions easier and us-versus-them rifts less likely. The first colonies will also need to number between 10,000 and 11,000 individuals to ensure enough genetic diversity to protect against evolutionary concepts such as genetic drift and population crashes.

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Amusingly, the one part of human activity most important for a sustainable colony – procreation – is the most understudied. When a NASA scientist made the suggestion a colony would need private spaces with soundproof walls, the backlash was so severe that NASA had to reassure Congress that taxpayer dollars were not being “wasted” encouraging sexual activity among astronauts.

Solomon’s writing is concise yet extraordinarily thorough – there is always just enough for you to feel you can understand the importance and nuance of topics ranging from Apollo-era health studies to evolution, and from AI to genetic engineering. The book is impeccably researched, and he presents conflicting ethical viewpoints so deftly, and without apparent judgement, that you are left plenty of space to imprint your own opinions. So much so that when Solomon shares his own stance on the colonization of Mars in the epilogue, it comes as a bit of a surprise.

In essence, this book lays out a convincing argument that it might be our biology, not our technology, that limits humanity’s expansion to Mars. And if we are able to overcome those limitations, either with purposeful genetic engineering or passive evolutionary change, this could mean we have shed our humanity.

Becoming Martian is one of the best popular-science books I have read within the field, and it is an uplifting read, despite dealing with some of the heaviest ethical questions in space sciences. Whether you’re planning your future as a Martian or just wondering if humans can have sex in space, this book should be on your wish list.

February 2026 MIT Press 264pp £27hb

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+ + + + https://physicsworld.com/?p=130004 + Sunlight may provide an energy-efficient alternative to lasers used in quantum computing

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Honor Powrie: 10 things I wish I’d known (or done better) when I started my career

Honor Powrie — Mon, 24 Aug 2026 13:00:24 +0000

When I went to university, I didn’t know what kind of career I wanted to pursue. I’d originally applied to study geophysics, but after a few weeks realized mineral exploitation wasn’t my thing and quickly switched to maths. Then, at the end of my first year, I had a range of degree options open to me and, whilst I preferred (and was better at) maths, I just didn’t feel it was my best choice for a career.

So I decided to switch again, this time to physics. During my degree, a few friends and I joined the Student Industrial Society (now known as the Bright Future Society). It gave us the chance to visit a range of companies – from micro-breweries and wine importers to TV studios, nuclear-power stations and semiconductor manufacturers. We also went to Llanwern steelworks in South Wales, where a closing session with a British Steel careers advisor really shook me up.

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A feisty Yorkshireman, he started off by directly asking each of us what we planned to do after university. We were all put on the spot and our answers, which were embarrassingly unsure, failed to impress him. The advisor firmly suggested that if we didn’t know what our plans were by now, we had better find out before it was too late. For me, it was a wake-up call and when I got back to campus, I went straight to the careers office and started applying for summer student placements.

To my amazement, and despite my lack of experience, I was offered several positions and decided to take a summer job in Malvern at the Royal Signals and Radar Establishment, which is now part of the private defence-technology firm QinetiQ. Somehow, I managed to find something useful to work on and after 12 weeks had done enough to be as included as co-author on a peer-reviewed publication.

Summerlove sensation

After the placement, I continued with my physics degree, but began to feel something about physics wasn’t quite right for me. Whilst I loved the classical side of the subject and the real-world applications, I struggled with the less visible aspects, such as quantum and nuclear. So after a final-year project investigating the aerodynamics of cars – and finding myself more interested in my housemate’s mechanical engineering course – I wondered if I might be better suited to a career in engineering.

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On the back of this growing interest, I applied to do a PhD in high-speed aerodynamics at the University of Southampton. My final-year project – coupled with my grounding in physics and the fact that I had a journal publication to my name – must have impressed my future supervisor, who picked me for the project. I had a great time on my PhD, which proved I loved engineering – particularly aerospace.

After four years in research, I realized an academic career wasn’t for me. But my PhD proved handy as it led to me getting a job with a small business called Stewart Hughes Ltd, which built vibration-monitoring equipment for use on mechanical machines. The company was looking for people with an academic background whose presence could help secure US government research funding. It turned out to be a sound strategy, as the firm built up a significant track record in winning high-value government grants.

My advice to you

These days I work a lot with interns and science or engineering students, who often ask me about my career path. As you can see, it wasn’t straightforward – and I believe a lot of people struggle making choices early in their careers. It’s easy to think you need to have everything mapped out in advance, which is rarely how things pan out. With that in mind, here are a few tips if you are starting out on your own career journey.

Top 10 tips

1 Even if you’re not sure what’s right for you – just try things out. Visiting industrial sites or attending topical lectures is great, even if it doesn’t lead to any work experience.

2 Be honest about what you like and don’t like – and don’t be afraid to change direction if things don’t feel right.

3 Be prepared to stretch yourself to find out more. Go outside your comfort zone.

4 Remember your degree subject may not be the most important thing unless you’re aiming for a career needing specific vocational training to get in. It’s far more important to study a subject you enjoy.

5 Get yourself a mentor who can be a constant in your career. They don’t have to be more senior to you; they could be a peer or someone more junior (i.e. a “reverse mentor”).

6 It’s fine if you enjoy doing lots of different things – but it doesn’t mean you have to do them all at once.

7 Being happy in what you do is more important than ultimate career goals.

8 Career opportunities don’t arise exactly when you’d like them to so be prepared to jump in or try different options if they pop up. A lateral move can be just as effective.

9 Don’t be afraid to nominate yourself for awards and prizes. An award will look good on your CV and there are a surprising number of opportunities.

10 Network and use your friends’ and peers’ experience.

Doing the rounds

One interesting bit of advice was once given to me on a career session led by a senior human-resources executive who works for a global corporation. The exec told us how he’d been having a golf lesson and was about to hit the ball down the fairway when the coach stopped him and asked where he was aiming. After explaining he was hoping to land the ball on the green, the coach shot back: “Yes…but where exactly on the green?”

Set your goal, do your best to reach it, and don’t worry too much about potential pitfalls.
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Obviously the exec said he wanted to get a hole in one, but he was also trying to avoid the bunker and the long grass. The coach went on to explain that golfers should aim at the target and not be distracted by obstacles. Stay focused and the ball will land at or near the target. The exec saw this as the perfect analogy for one’s career: set your goal, do your best to reach it, and don’t worry too much about potential pitfalls.

Now that’s easier said than done – in fact, my career journey has not been the epitome of this advice. There have been bumps and detours along the way, which haven’t necessarily been through lack of focus, but because it took me time to discover what I really wanted to do. To stretch the golf analogy to breaking point, my first green might have not been great, but I’ve certainly had fun making it round the course.

The post Honor Powrie: 10 things I wish I’d known (or done better) when I started my career appeared first on Physics World.

Solar storms could be forecast by monitoring cosmic rays

No Author — Wed, 14 Jan 2026 08:33:19 +0000

Using incidental data collected by the BepiColombo mission, an international research team has made the first detailed measurements of how coronal mass ejections (CMEs) reduce cosmic-ray intensity at varying distances from the Sun. Led by Gaku Kinoshita at the University of Tokyo, the team hopes that their approach could help improve the accuracy of space weather forecasts following CMEs.

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CMEs are dramatic bursts of plasma originating from the Sun’s outer atmosphere. In particularly violent events, this plasma can travel through interplanetary space, sometimes interacting with Earth’s magnetic field to produce powerful geomagnetic storms. These storms result in vivid aurorae in Earth’s polar regions and can also damage electronics on satellites and spacecraft. Extreme storms can even affect electrical grids on Earth.

To prevent such damage, astronomers aim to predict the path and intensity of CME plasma as accurately as possible – allowing endangered systems to be temporarily shut down with minimal disruption. According to Kinoshita’s team, one source of information has so far been largely unexplored.

Pushing back cosmic rays

Within interplanetary space, CME plasma interacts with cosmic rays, which are energetic charged particles of extrasolar origin that permeate the solar system with a roughly steady flux. When an interplanetary CME (ICME) passes by, it temporarily pushes back these cosmic rays, creating a local decrease in their intensity.

“This phenomenon is known as the Forbush decrease effect,” Kinoshita explains. “It can be detected even with relatively simple particle detectors, and reflects the properties and structure of the passing ICME.”

In principle, cosmic-ray observations can provide detailed insights into the physical profile of a passing ICME. But despite their relative ease of detection, Forbush decreases had not yet been observed simultaneously by detectors at multiple distances from the Sun, leaving astronomers unclear on how propagation distance affects their severity.

Now, Kinoshita’s team have explored this spatial relationship using BepiColombo, a European and Japanese mission that will begin orbiting Mercury in November 2026. While the mission focuses on Mercury’s surface, interior, and magnetosphere, it also carries non-scientific equipment capable of monitoring cosmic rays and solar plasma in its surrounding environment.

“Such radiation monitoring instruments are commonly installed on many spacecraft for engineering purposes,” Kinoshita explains. “We developed a method to observe Forbush decreases using a non-scientific radiation monitor onboard BepiColombo.”

Multiple missions

The team combined these measurements with data from specialized radiation-monitoring missions, including ESA’s Solar Orbiter, which is currently probing the inner heliosphere from inside Mercury’s orbit, as well as a network of near-Earth spacecraft. Together, these instruments allowed the researchers to build a detailed, distance-dependent profile of a week-long ICME that occurred in March 2022.

Just as predicted, the measurements revealed a clear relationship between the Forbush decrease effect and distance from the Sun.

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“As the ICME evolved, the depth and gradient of its associated cosmic-ray decrease changed accordingly,” Kinoshita says.

With this method now established, the team hopes it can be applied to non-scientific radiation monitors on other missions throughout the solar system, enabling a more complete picture of the distance dependence of ICME effects.

“An improved understanding of ICME propagation processes could contribute to better forecasting of disturbances such as geomagnetic storms, leading to further advances in space weather prediction,” Kinoshita says. In particular, this approach could help astronomers model the paths and intensities of solar plasma as soon as a CME erupts, improving preparedness for potentially damaging events.

The research is described in The Astrophysical Journal.

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+ Earthquake sensors reveal vital information about how hurricanes move and grow + https://physicsworld.com/a/earthquake-sensors-reveal-vital-information-about-how-hurricanes-move-and-grow/ + Mon, 24 Aug 2026 12:39:39 +0000 + + + + + https://physicsworld.com/?p=129957 + Seismic stations in Louisiana have been found to provide insights into Hurricane Isaac

The post Earthquake sensors reveal vital information about how hurricanes move and grow appeared first on Physics World.

Protons and neutrons are more than just groups of three quarks

Tim Wogan — Mon, 24 Aug 2026 08:30:41 +0000

Particles such as protons and neutrons are more accurately represented as “baryon junctions” than as simple collections of three quarks, say physicists. This finding, which is based on studies of heavy-ion collisions, is at odds with textbook descriptions, but it confirms a longstanding belief among many nuclear physicists that these descriptions are over-simplified.

Like charge and energy, baryon number is conserved in all experimentally observed reactions. This conservation law was first articulated in 1938, long before physicists developed the theory of quantum chromodynamics (QCD) to explain the behaviour of nuclei. It also predates the coinage of the term “quark” by Murray Gell-Mann in 1963.

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Initially, theorists working on QCD felt that the simplest way to incorporate baryon number conservation was to assign a baryon number of 1/3 to every quark and -1/3 to every antiquark. As bound states of three quarks, protons and other baryons therefore have a baryon number of +1, antibaryons are -1, and quark-antiquark pairs, or mesons, are 0. However, this association of the baryon number with the quark – known as the valence quark model – is not fundamental to QCD, and as early as the 1970s theorists were already considering alternatives. In 1996, for example, Dmitri Kharzeev of Stony Brook University in New York, US proposed a model in which the baryon number was assigned not to the quarks themselves but to the Y-shaped junction in the gluon field that mediates their interactions.

At high-energy accelerators such as the LHC, collisions are usually modelled in the high-energy “perturbative QCD” regime. Here, quarks can be treated as isolated particles, and the two models are effectively equivalent. Inside a proton or in a quark-gluon plasma, however, quarks are more deeply immersed in the gluon field. This makes perturbative calculations such as those used in the theory of quantum electrodynamics (QED) impossible. “You can’t do these Feynman-like calculations anymore,” explains Anselm Vossen, an experimental nuclear physicist at Duke University in North Carolina, US. “Every diagram you write out has the same importance.” Within this so-called “lattice QCD” regime, the two models’ predictions can differ.

Discrepancies between models

In the new work, the STAR collaboration – which studies particles produced in quark-gluon plasmas generated at Brookhaven National Laboratory’s Relativistic Heavy Ion Collider (RHIC) in New York, US – homed in on these differences. By comparing predictions from the baryon junction model with those from the valence quark model in various scenarios, and matching them against experimental results, they hoped to find evidence to support one model over another.

First, they studied head-on collisions of gold nuclei, plus near-misses that led to the exchange of a virtual photon and the break-up of one nucleus. They found that the proportion of particles scattered varied sharply with the energy of the incoming nuclei, but not as the valence quark model predicted.

“The net baryons scattered decreases as the beam energy increases – that is expected – because the higher the energy the more things will just move straight through without being scattered to a large angle,” explains Chun Yuen Tsang, a STAR project leader who is now at Argonne National Laboratory in Illinois. However, he adds that the rate of decline “is actually slower than the existing valence quark model would have you believe”. A baryon junction should scatter more easily than a valence quark, so the fact that a simulation designed using the latter model underpredicts scattering at high energies points towards the baryon junction model.

A charged result

The researchers also compared fragments produced in collisions with zirconium-96 and rubidium-96 nuclei. Since both particles contain the same number of nucleons, they have the same baryon number. However, the ruthenium-96 nucleus has 44 protons, whereas the zirconium-96 nucleus has only 40, giving them different electric charges.

In a nuclear collision, both charge and baryon number – while being conserved overall – are rearranged among the fragments. The charge is localized to the quarks, so, according to the valence quark model, charge and baryon number should move approximately the same amount. Because the colliding nuclear pairs in this experiment differed only in their charge, the outcomes of collisions could be predicted relatively well across a range of energies. However, these predictions were strongly violated, with baryon number moving much more easily than electric charge. “This is evidence for quarks not being the carriers of both baryon number and electric charge,” Tsang says.

The researchers now wish to study collisions from other experiments. They also hope that the Electron-Ion Collider currently planned to replace RHIC will provide a more precise baryon probe and yield a definitive answer.

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Vossen, who was not involved in the research, says that in some sense, its conclusions are “not that surprising”. His own research has examined the so-called “proton spin crisis” precipitated by the discovery that the proton’s spin cannot be explained by the spin of its constituent quarks, while the proton’s mass is much greater than the sum of the quark masses. “It’s part of this general picture that shows that a proton is much more complex than three valence quarks,” he says. Nevertheless, he says the STAR findings are not trivial: “It’s still a very interesting result,” he concludes.

The work is published in Science.

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CERN team solves decades-old mystery of light nuclei formation

No Author — Tue, 13 Jan 2026 14:00:29 +0000

When particle colliders smash particles into each other, the resulting debris cloud sometimes contains a puzzling ingredient: light atomic nuclei. Such nuclei have relatively low binding energies, and they would normally break down at temperatures far below those found in high-energy collisions. Somehow, though, their signature remains. This mystery has stumped physicists for decades, but researchers in the ALICE collaboration at CERN have now figured it out. Their experiments showed that light nuclei form via a process called resonance-decay formation – a result that could pave the way towards searches for physics beyond the Standard Model.

Baryon resonance

The ALICE team studied deuterons (a bound proton and neutron) and antideuterons (a bound antiproton and antineutron) that form in experiments at CERN’s Large Hadron Collider. Both deuterons and antideuterons are fragile, and their binding energies of 2.2 MeV would seemingly make it hard for them to form in collisions with energies that can exceed 100 MeV – 100 000 times hotter than the centre of the Sun.

+ The collaboration found that roughly 90% of the deuterons seen after such collisions form in a three-phase process. In the first phase, an initial collision creates a so-called baryon resonance, which is an excited state of a particle made of three quarks (such as a proton or neutron). This particle is called a Δ baryon and is highly unstable, so it rapidly decays into a pion and a nucleon (a proton or a neutron) during the second phase of the process. Then, in the third (and, crucially, much later) phase, the nucleon cools down to a point where its energy properties allow it to bind with another nucleon to form a deuteron.

Smoking gun

Measuring such a complex process is not easy, especially as everything happens on a length scale of femtometres (10^-15 meter). To tease out the details, the collaboration performed precision measurements to correlate the momenta of the pions and deuterons. When they analysed the momentum difference between these particle pairs, they observed a peak in the data corresponding to the mass of the Δ baryon. This peak shows that the pion and the deuteron are kinematically linked because they share a common ancestor: the pion came from the same Δ decay that provided one of the deuteron’s nucleons.

Panos Christakoglou, a member of the ALICE collaboration based at the Netherlands’ Maastricht University, says the experiment is special because in contrast to most previous attempts, where results were interpreted in light of models or phenomenological assumptions, this technique is model-independent. He adds that the results of this study could be used to improve models of high energy proton-proton collisions in which light nuclei (and maybe hadrons more generally) are formed. Other possibilities include improving our interpretations of cosmic-ray studies that measure the fluxes of (anti)nuclei in the galaxy – a useful probe for astrophysical processes.

The hunt is on

Intriguingly, Christakoglou suggests that the team’s technique could also be used to search for indirect signs of dark matter. Many models predict that dark-matter candidates such as Weakly Interacting Massive Particles (WIMPs) will decay or annihilate in processes that also produce Standard Model particles, including (anti)deuterons. “If for example one measures the flux of (anti)nuclei in cosmic rays being above the ‘Standard Model based’ astrophysical background, then this excess could be attributed to new physics which might be connected to dark matter,” Christakoglou tells Physics World.

Michael Kachelriess, a physicist at the Norwegian University of Science and Technology in Trondheim, Norway, who was not involved in this research, says the debate over the correct formation mechanism for light nuclei (and antinuclei) has divided particle physicists for a long time. In his view, the data collected by the ALICE collaboration decisively resolves this debate by showing that light nuclei form in the late stages of a collision via the coalescence of nucleons. Kachelriess calls this a “great achievement” in itself, and adds that similar approaches could make it possible to address other questions, such as whether thermal plasmas form in proton-proton collisions as well as in collisions between heavy ions.

The post CERN team solves decades-old mystery of light nuclei formation appeared first on Physics World.

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Fancy some more? Check out our puzzles page.

The post Quiz of the week: where does new research say the universe’s ‘missing’ baryonic matter is? appeared first on Physics World.

Anyon physics could explain coexistence of superconductivity and magnetism

No Author — Tue, 13 Jan 2026 08:45:52 +0000

Researchers at the Flatiron Institute in New York City have used a new tensor network (TN) scheme to simulate how Ising spin glasses evolve in time. In many cases, their classical method is more accurate than the latest quantum annealers running the same problem. The results scale in two and three dimensions and raise the bar in the ongoing competition between classical and quantum computers for simulating many-particle quantum systems.

Classical versus quantum

Quantum many-particle systems provide a good way of comparing computational techniques because their complexity grows exponentially with the number of particles. In theory, quantum computers hold an advantage rooted in entanglement and superposition. In a classical computer, the spin of a particle (up or down) is encoded in bit that is either zero (down) or one (up), but never both. In a quantum computer, the spin can be encoded in a qubit holding a quantum superposition of up and down. This is a much more natural way to represent what the simulated system is actually doing.

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Recently, a team of quantum computing researchers used the D-Wave’s Advantage2 quantum annealer to simulate Ising spin glass dynamics and claimed that classical computers could not match their results. But now, Joseph Tindall and colleagues at the Flatiron Institute have shown that a classical scheme can do just as well -and sometimes better- than the annealer.

In this occasion, the competition involved the simulation of the Ising spin glass model, which describes spins on a lattice pointing in random directions. This disordered state is product of different nearest-neighbor interactions for different pairs of spins. The difficulty of this famous problem grows with the system size, which makes it a good benchmark for comparing classical and quantum performance.

Tensor networks

The tensors used by Tindall and colleagues can be thought of as LEGO pieces. Just as LEGO bricks have knobs and tubes that snap together to build a bigger array, tensors have legs (bond indices) that join through a process called contraction to form networks. In a many-particle simulation, each tensor represents a site along with its physical attributes: for instance, the type of particle it hosts, which could be a spin or an electron. Connected together, the tensors form a network that encodes how those particles interact and how entangled they are. Widening the legs (increasing the bond dimension in technical terms), allows the network to capture the correlations more accurately.

In simple terms, the pattern of connections describes how particles can move or interact, and what Tindall and colleagues built is a tensor network representation of both the Ising spin glass Hamiltonian and wave function. The first specifies the interactions between spins and the second describes the state of spins. Writing quantum states this way has proved enormously useful for accessing large systems, where the sheer number of particles rules out any exact solution.

Tindall’s group used these tensor network ideas to simulate the spin glass model’s dynamics. But there is a catch: as a TN wave function evolves forward in time, entanglement builds up between different parts of the system and the bond indices must widen to keep track of the growing correlations. This increases the computational cost of finding the ground state of the system at different times, making it more difficult and sometimes impossible.

Belief propagation

To compensate for this, the team used a belief propagation (BP) message passing approach to perform the contraction. In this scheme, each tensor receives a compact summary of what the rest of the network “looks like” from its perspective (the effective environment of each tensor). This unlike the conventional approach of accounting for every single contribution exactly. As Tindall points out, their approach can be understood as a mean field approximation on each tensor’s environment since the pieces of information reaching a particular given tensor from each of its neighbours are assumed to be independent.

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By implementing this TN–BP approach, their classical implementation could evolve the system to much longer times than conventional TN schemes and manage far enough to reach the regime the quantum annealer operates. Conceptually, passing messages about an effective environment lets the computation to keep pace with the entanglement inherent to the system’s time evolution. The researchers then measured how the spin at one site relates to the spin elsewhere on the lattice (the two-point correlator) at various times and system sizes on two and three-dimensional lattices with cylindrical, diamond and cubic geometries.

Starting with a cylindrical lattice, the team compared the error in the two-point correlator error from the annealer with that from the TN-BP message passing approach. Once the bond dimension was large enough, the classical error was markedly lower error than the quantum counterpart at different annealing. On the diamond lattice, the classical error obtained again came in below the annealer’s, while on the cubic lattice the error was of the same order at a fixed annealing time.

What comes next

This work, which is described in Science, shows how fast classical simulation of quantum physics is advancing and how the on-going competition between classical and quantum computation is driving this progress. In the future, Tindall and colleagues want to apply the TB-BP to interacting electronic systems such the Hubbard model. Additionally, the group is also extending their scheme to finite temperature problems as well as maintaining their open-source tensor network quantum simulator library.

The post No quantum advantage (yet) in the world of tensor networks appeared first on Physics World.

Can entrepreneurship be taught? An engineer’s viewpoint

Honor Powrie — Mon, 12 Jan 2026 11:00:54 +0000

I am intrigued by entrepreneurship. Is it something we all innately possess – or can entrepreneurship be taught to anyone (myself included) for whom it doesn’t come naturally? Could we all – with enough time, training and support – become the next Jeff Bezos, Richard Branson or Martha Lane Fox?

In my professional life as an engineer in industry, we often talk about the importance of invention and innovation. Without them, products will become dated and firms will lose their competitive edge. However, inventions don’t necessarily sell themselves, which is where entrepreneurs have a key influence.

So what’s the difference between inventors, innovators and entrepreneurs? An inventor, to me, is someone who creates a new process, application or machine. An innovator is a person who introduces something new or does something for the first time. An entrepreneur, however, is someone who sets up a business or takes on a venture, embracing financial risks with the aim of profit.

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Scientists and engineers are naturally good inventors and innovators. We like to solve problems, improve how we do things, and make the world more ordered and efficient. In fact, many of the greatest inventors and innovators of all time were scientists and engineers – think James Watt, George Stephenson and Frank Whittle.

But entrepreneurship requires different, additional qualities. Many entrepreneurs come from a variety of different backgrounds – not just science and engineering – and tend to have finance in their blood. They embrace risk and have unlimited amounts of courage and business acumen – skills I’d need to pick up if I wanted to be an entrepreneur myself.

Risk and reward

Engineers are encouraged to take risks, exploring new technologies and designs; in fact, it’s critical for companies seeking to stay competitive. But we take risks in a calculated and professional manner that prioritizes safety, quality, regulations and ethics, and project success. We balance risk taking with risk management, spotting and assessing potential risks – and mitigating or removing them if they’re big.

Courage is not something I’ve always had professionally. Over time, I have learned to speak up if I feel I have something to say that’s important to the situation or contributes to our overall understanding. Still, there’s always a fear of saying something silly in front of other people or being unable to articulate a view adequately. But entrepreneurs have courage in their DNA.

So can entrepreneurship be taught? Specifically, can it be taught to people like me with a technical background – and, if so, how? Some of the most famous innovators, like Henry Ford, Thomas Edison, Steve Jobs, James Dyson and Benjamin Franklin, had scientific or engineering backgrounds, so is there a formula for making more people like them?

Skill sets and gaps

Let’s start by listing the skills that most engineers have that could be beneficial for entrepreneurship. In no particular order, these include:

problem-solving ability: essential for designing effective solutions or to identify market gaps;
innovative mindset: critical for building a successful business venture;
analytical thinking: engineers make decisions based on data and logic, which is vital for business planning and decision making;
persistence: a pre-requisite for delivering engineering projects and needed to overcome the challenges of starting a business;
technical expertise: a significant competitive advantage and providing credibility, especially relevant for tech start-ups.

However, there are mindset differences between engineers and entrepreneurs that any training would need to overcome. These include:

risk tolerance: engineers typically focus on improving reliability and reducing risk, whilst entrepreneurs are more comfortable with embracing greater uncertainty;
focus: engineers concentrate on delivering to requirements, whilst entrepreneurs focus on consumer needs and speed to market;
business acumen: a typical engineering education doesn’t cover essential business skills such as marketing, sales and finance, all of which are vital for running a company.

Such skills may not always come naturally to engineers and scientists, but they can be incorporated into our teaching and learning. Some great examples of how to do this were covered in Physics World last year. In addition, there is a growing number of UK universities offering science and engineering degrees combined with entrepreneurship.

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The message is that whilst some scientists and engineers become entrepreneurs, not all do. Simply having a science or engineering background is no guarantee of becoming an entrepreneur, nor is it a requirement. Nevertheless, the problem-solving and technical skills developed by scientists and engineers are powerful assets that, when combined with business acumen and entrepreneurial drive, can lead to business success.

Of course, entrepreneurship may not suit everybody – and that’s perfectly fine. No-one should be forced to become an entrepreneur if they don’t want to. We all need to play to our core strengths and interests and build well-rounded teams with complementary skillsets – something that every successful business needs. But surely there’s a way of teaching entrepreneurism too?

The post Can entrepreneurship be taught? An engineer’s viewpoint appeared first on Physics World.

+ Betelgeuse is not alone + https://physicsworld.com/a/betelgeuse-is-not-alone/ + Fri, 21 Aug 2026 11:00:55 +0000 + + + + https://physicsworld.com/?p=129960 + Orion constellation's red supergiant has a companion star, say astronomers

The post Betelgeuse is not alone appeared first on Physics World.

Shapiro steps spotted in ultracold bosonic and fermionic gases

No Author — Mon, 12 Jan 2026 08:00:00 +0000

Shapiro steps – a series of abrupt jumps in the voltage–current characteristic of a Josephson junction that is exposed to microwave radiation – have been observed for the first time in ultracold gases by groups in Germany and Italy. Their work on atomic Josephson junctions provides new insights into the phenomenon, and could lead to a standard for chemical potential.

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In 1962 Brian Josephson of the University of Cambridge calculated that, if two superconductors were separated by a thin insulating barrier, the phase difference between the wavefunctions on either side should induce quantum tunneling, leading to a current at zero potential difference.

A year later, Sidney Shapiro and colleagues at the consultants Arthur D. Little showed that inducing an alternating electric current using a microwave field causes the phase of the wavefunction on either side of a Josephson junction to evolve at different rates, leading to quantized increases in potential difference across the junction. The height of these “Shapiro steps” depends only on the applied frequency of the field and the electrical charge. This is now used as a reference standard for the volt.

Researchers have subsequently developed analogues of Josephson junctions in other systems such as liquid helium and ultracold atomic gases. In the new work, two groups have independently observed Shapiro steps in ultracold quantum gases. Instead of placing a fixed insulator in the centre and driving the system with a field, the researchers used focused laser beams to create potential barriers that divided the traps into two. Then they moved the positions of the barriers to alter the potentials of the atoms on either side.

Current emulation

“If we move the atoms with a constant velocity, that means there’s a constant velocity of atoms through the barrier,” says Herwig Ott of RPTU University Kaiserslautern-Landau in Germany, who led one of the groups. “This is how we emulate a DC current. Now for the Shapiro protocol you have to apply an AC current, and the AC current you simply get by modulating your barrier in time.”

Ott and colleagues in Kaiserslautern, in collaboration with researchers in Hamburg and the United Arab Emirates (UAE), used a Bose–Einstein condensate (BEC) of rubidium-87 atoms. Meanwhile in Italy, Giulia Del Pace of the European Laboratory for Nonlinear Spectroscopy at the University of Florence and colleagues (including the same UAE collaborators) studied ultracold lithium-6 atoms, which are fermions.

Both groups observed the theoretically-predicted Shapiro steps, but Ott and Del Pace explain that these observations do not simply confirm predictions. “The message is that no matter what your microscopic mechanism is, the phenomenon of Shapiro steps is universal,” says Ott. In superconductors, the Shapiro steps are caused by the breaking of Cooper pairs; in ultracold atomic gases, vortex rings are created. Nevertheless, the same mathematics applies. “This is really quite remarkable,” says Ott.

Del Pace says it was unclear whether Shapiro steps would be seen in strongly-interacting fermions, which are “way more interacting than the electrons in superconductors”. She asks, “Is it a limitation to have strong interactions or is it something that actually helps the dynamics to happen? It turns out it’s the latter.”

Magnetic tuning

Del Pace’s group applied a variable magnetic field to tune their system between a BEC of molecules, a system dominated by Cooper pairs and a unitary Fermi gas in which the particles were as strongly interacting as permitted by quantum mechanics. The size of the Shapiro steps was dependent on the strength of the interparticle interaction.

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Ott and Del Pace both suggest that this effect could be used to create a reference standard for chemical potential – a measure of the strength of the atomic interaction (or equation of state) in a system.

“This equation of state is very well known for a BEC or for a strongly interacting Fermi gas…but there is a range of interaction strengths where the equation of state is completely unknown, so one can imagine taking inspiration from the way Josephson junctions are used in superconductors and using atomic Josephson junctions to study the equation of state in systems where the equation of state is not known,” explains Del Pace.

The two papers are published side by side in Science: Del Pace and Ott.

Rocío Jáuregui Renaud of the Autonomous University of Mexico is impressed, especially by the demonstration in both bosons and fermions. “The two papers are important, and they are congruent in their results, but the platform is different,” she says. “At this point, the idea is not to give more information directly about superconductivity, but to learn more about phenomena that sometimes you are not able to see in electronic systems but you would probably see in neutral atoms.”

The post Shapiro steps spotted in ultracold bosonic and fermionic gases appeared first on Physics World.

+ Colliding molecules reveal their ‘cone of reaction’ + https://physicsworld.com/a/colliding-molecules-reveal-their-cone-of-reaction/ + Fri, 21 Aug 2026 08:00:32 +0000 + + + + https://physicsworld.com/?p=129937 + New measurements advance our understanding of chemical reactions at the atomic scale and could shape our ability to optimize them

The post Colliding molecules reveal their ‘cone of reaction’ appeared first on Physics World.

Watching how grasshoppers glide inspires new flying robot design

Michael Banks — Fri, 09 Jan 2026 14:43:34 +0000

Molecularly imprinted polymers (MIPs) are synthetic receptors that can recognize target analytes through tailored binding sites, offering a stable, cost-effective and versatile alternative to natural bioreceptors. In electrochemical sensing, MIPs have attracted growing interest because they can provide high selectivity while enabling rapid, portable and low-cost detection.

This webinar will introduce the fundamentals of molecular imprinting, including binding site design, polymerization strategies, template removal and immobilization on electrode surfaces. It will then compare molecularly imprinted non-conducting polymers (MINPs) and molecularly imprinted conducting polymers (MICPs), focusing on their differences in conductivity, binding-site accessibility, reproducibility, sensitivity and selectivity. Recent advances in MIP-based electrochemical sensors will be discussed across representative applications, along with current limitations and design strategies to improve sensor performance.

The webinar will conclude with perspectives on how conducting polymers, nanomaterials and optimized molecular recognition can guide the development of next-generation selective and sensitive electrochemical sensors.

+ +

Wonhyeong Kim

Wonhyeong Kim is a postdoctoral research associate in the department of materials science and engineering at the University of Arizona. He received his PhD in materials engineering from Auburn University, where his research focused on molecularly imprinted polymers, conducting polymers and electrochemical sensors for selective chemical and biomarker detection. His work has resulted in multiple publications in leading journals and he was the recipient of the 2025 ECS Sensor Division Student Research Award for his contributions to molecularly imprinted polymer-based electrochemical sensors. His research interests include molecular imprinting, conducting polymers, electrochemical sensors and functional materials for selective chemical sensing, with recent work expanding into advanced polymeric materials and nanomaterials for environmental applications.

The post Advances in molecularly imprinted polymers for electrochemical sensing appeared first on Physics World.

Cracking the limits of clocks: a new uncertainty relation for time itself

Jessica Tucker — Fri, 09 Jan 2026 12:00:03 +0000

What if a chemical reaction, ocean waves or even your heartbeat could all be used as clocks? That’s the starting point of a new study by Kacper Prech, Gabriel Landi and collaborators, who uncovered a fundamental, universal limit to how precisely time can be measured in noisy, fluctuating systems. Their discovery – the clock uncertainty relation (CUR) – doesn’t just refine existing theory, it reframes timekeeping as an information problem embedded in the dynamics of physical processes, from nanoscale biology to engineered devices.

The foundation of this work contains a simple but powerful reframing: anything that “clicks” regularly is a clock. In the research paper’s opening analogy, a castaway tries to cook a fish without a wristwatch. They could count bird calls, ocean waves, or heartbeats – each a potential timekeeper with different cadence and regularity. But questions remain: given real-world fluctuations, what’s the best way to estimate time, and what are the inescapable limits?

The authors answer both. They show for a huge class of systems – those described by classical, Markovian jump processes (systems where the future depends only on the present state, not the past history – a standard model across statistical physics and biophysics) – there is a tight achievable bound on timekeeping precision. The bound is controlled not by how often the system jumps on average (the traditional “dynamical activity”), but by a subtler quantity: the mean residual time, or the average time you’d wait for the next event if you start observing at a random moment. That distinction matters.

The inspection paradox The graphic illustrates the mean residual time used in the CUR and how it connects to the so-called inspection paradox – a counterintuitive bias where randomly arriving observers are more likely to land in longer gaps between events. Buses arrive in clusters (gaps of 5 min) separated by long intervals (15 min), so while the average time between buses might seem moderate, a randomly arriving passenger (represented by the coloured figures) is statistically more likely to land in one of the long 15-min gaps than in a short 5-min one. The mean residual time is the average time a passenger waits for their bus if they arrive at the bus stop at a random time. Counterintuitively, this can be much longer than the average time between buses. The visual also demonstrates why the mean residual time captures more information than the simple average interval, since it accounts for the uneven distribution of gaps that biases your real waiting experience. (Courtesy: IOP Publishing)

The study introduces CUR, a universal, tight bound on timekeeping precision that – unlike earlier bounds – can be saturated and the researchers identify the exact observables that achieve this limit. Surprisingly, the optimal strategy for estimating time from a noisy process is remarkably simple: sum the expected waiting times of each observed state along the trajectory, rather than relying on complex fitting methods. The work also reveals that the true limiting factor for precision isn’t the traditional dynamical activity, but rather the inverse of the mean residual time. This makes the CUR provably tighter than the earlier kinetic uncertainty relation, especially in systems far from equilibrium.

+ The team also connects precision to two practical clock metrics: resolution (how often a clock ticks) and accuracy (how many ticks before it drifts by one tick.) In other words, achieving steadier ticks comes at the cost of accepting fewer of them per unit of time.

This framework offers practical tools across several domains. It can serve as a diagnostic for detecting hidden states in complex biological or chemical systems: if measured event statistics violate the CUR, that signals the presence of hidden transitions or memory effects. For nanoscale and molecular clocks – like biomolecular oscillators (cellular circuits that produce rhythmic chemical signals) and molecular motors (protein machines that walk along cellular tracks) – the CUR sets fundamental performance limits and guides the design of optimal estimators. Finally, while this work focuses on classical systems, it establishes a benchmark for quantum clocks, pointing toward potential quantum advantages and opening new questions about what trade-offs emerge in the quantum regime.

Landi, an associate professor of theoretical quantum physics at the University of Rochester, emphasizes the conceptual shift: that clocks aren’t just pendulums and quartz crystals. “Anything is a clock,” he notes. The team’s framework “gives the recipe for constructing the best possible clock from whatever fluctuations you have,” and tells you “what the best noise-to-signal ratio” can be. In everyday terms, the Sun is accurate but low-resolution for cooking; ocean waves are higher resolution but noisier. The CUR puts that intuition on firm mathematical ground.

Looking forward, the group is exploring quantum generalizations and leveraging CUR-violations to infer hidden structure in biological data. A tantalizing foundational question lingers: can robust biological timekeeping emerge from many bad, noisy clocks, synchronizing into a good one?

Ultimately, this research doesn’t just sharpen a bound; it reframes timekeeping as a universal inference task grounded in the flow of events. Whether you’re a cell sensing a chemical signal, a molecular motor stepping along a track or an engineer building a nanoscale device, the message is clear: to tell time well, count cleverly – and respect the gaps.

The research is detailed in Physical Review X.

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Image courtesy: iStock/guirong hao

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Bidirectional scattering microscope detects micro- and nanoscale structures simultaneously

Isabelle Dumé — Fri, 09 Jan 2026 10:00:59 +0000

Newborn and rapidly growing supermassive black holes could be powering the mysterious “little red dots” that litter the early universe. That is the conclusion of an international team of astronomers who have found the best evidence yet for a new kind of object called a “black-hole star”, which appears to be driving a little red dot that existed just 660 million years after the Big Bang.

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“A little red dot is an extraordinary object,” says team leader Rohan Naidu, of the University of Hawaii and MIT. “Somewhere within it lies a black-hole star, surrounded by a good old fashioned galaxy.”

When the James Webb Space Telescope (JWST) began observing the distant universe in the summer of 2022, astronomers were astonished to find lots of little red dots. They are highly luminous as one would expect an active black hole to be, but their spectra are odd, looking more like stars with no X-ray emission.

Some astronomers believe little red dots are dense cocoons of gas incubating a growing black hole at their cores. As the black hole accretes gas from the interior of the cocoon, it radiates energy that is absorbed by the cocoon – making it glow brightly. This is similar to how stars shine, the radiation from their core heating their outer layers. Hence these hypothesized objects are dubbed black-hole stars.

Until now, however there had only been circumstantial evidence for this hypothesis. Part of the problem is that in most cases the light from the little red dots mingles with the light from the unresolved host galaxy, clouding the observations.

Miracle or mirage?

Naidu is co-lead of the Mirage or Miracle (MoM) survey. When pushing to high redshifts (further distances) with the JWST, it can be difficult to discern whether a faint red splotch is really a high-redshift galaxy or a cool star in the foreground masquerading as something from the early universe.

Now, MoM has found a black-hole star shining 100 billion times brighter than any known star, and drastically outshining its host galaxy.

Called MoM-BH*-1, the object is incredibly luminous at longer wavelengths, but below the wavelength corresponding to the Balmer series of hydrogen emission there is no light at all. This sudden drop in luminosity is called the Balmer break and is often seen in young stars.

“In MoM-BH*-1 the Balmer break is three to four times stronger than any we’ve seen ever before,” says Naidu. “This feature alone tells us there is something truly singular afoot, and that this is a new kind of astrophysical object.”

Extremely dense cocoon

Simulations modelling the Balmer break and the object’s luminosity strongly suggest that there is a 100,000 solar mass black hole at the centre of MoM-BH*-1, surrounded by an extremely dense cocoon of gas.

“The physics of how its light is being produced by this dense gas cocoon around this black hole is radically different from what we see around us in the local universe,” says Naidu.

If the object is indeed a black-hole star, a salient question is how did the black hole form? Numerous possibilities have been raised, from the direct gravitational collapse of a gas cloud to the merger of a cluster of massive stars.

Naidu favours an explanation involving a supermassive star – an object that could have formed about 150 million years after the Big Bang when the universe was dense with hydrogen and helium. According to many popular models, these conditions spawned stars thousands of times the mass of the Sun.

Recent outburst

Naidu points to the life cycles of the massive stars in the Milky Way, which top out at a few hundred solar masses. Eta Carinae, for example, had an outburst in the 1840s that made it the second brightest star in the sky for several days. The outburst from this 100-solar-mass star left a cocoon of gas called the Homunculus Nebula. A much larger supermassive star could have had a similar outburst and then collapse to a black hole, thereby creating a black hole star.

“In the past few months I’ve seen so much evidence for this, that at this point, it is the main hypothesis that needs to be proved or disproved because the similarities to supermassive stars are uncanny,” says Naidu.

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Indeed, it is possible that every supermassive black hole in the universe could be a relic of the very first giant stars created just after the Big Bang. Over time these objects would steadily erode their gaseous cocoon, eating it away from the inside-out while radiation from accretion onto the black hole would blow away the remainder of the cocoon. This is supported by a recent discovery by NASA’s Chandra X-ray Observatory of a little red dot that existed 11.8 billion years ago and from which X-rays are starting to peak through holes in its shredded cocoon.

Naidu is suitably awe-struck by the possibilities, describing how “it’s inspiring to be witnessing the birth of supermassive black holes.”

The discovery of MoM-BH*-1 is reported in Nature.

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Quantum information theory sheds light on quantum gravity

Hamish Johnston — Thu, 08 Jan 2026 14:34:50 +0000

This episode of the Physics World Weekly podcast features Alex May, whose research explores the intersection of quantum gravity and quantum information theory. Based at Canada’s Perimeter Institute for Theoretical Physics, May explains how ideas being developed in the burgeoning field of quantum information theory could help solve one of the most enduring mysteries in physics – how to reconcile quantum mechanics with Einstein’s general theory of relativity, creating a viable theory of quantum gravity.

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This interview was recorded in autumn 2025 when I had the pleasure of visiting the Perimeter Institute and speaking to four physicists about their research. This is the last of those conversations to appear on the podcast.

The first interview in this series from the Perimeter Institute was with Javier Toledo-Marín, “Quantum computing and AI join forces for particle physics”; the second was with Bianca Dittrich, “Quantum gravity: we explore spin foams and other potential solutions to this enduring challenge“; and the third was with Tim Hsieh, “Building a quantum future using topological phases of matter and error correction”.

This episode of the Physics World Weekly podcast explores how the innate curiosity of children can help make quantum mechanics more accessible to the public. My guest is Katia Moskvitch, who co-hosts The Quantum Kid video channel with her 10-year-old son Kai.

As well as interviewing leading lights in quantum science and technology – including Nobel laureates – the duo has toured science labs including CERN. Moskvitch explains how the programme’s child-led approach puts guests at ease and helps them explain difficult concepts to a general audience.

Moskvitch believes that children can be more receptive to counterintuitive quantum concepts than adults and argues that an early familiarity with quantum physics could inspire young people to study science. This, she believes, will provide a foundation for success in the burgeoning quantum sector.

This episode is supported by the APS Global Physics Summit, which takes place on 15–20 March 2026 in Denver, Colorado, and online.

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Chess960 still results in white having an advantage, finds study

Michael Banks — Thu, 08 Jan 2026 13:43:26 +0000

Chess is a seemingly simple game, but one that hides incredible complexity. In the standard game, the starting positions of the pieces are fixed so top players rely on memorizing a plethora of opening moves, which can sometimes result in boring, predictable games. It’s also the case that playing as white, and therefore going first, offers an advantage.

In the 1990s, former chess world champion Bobby Fischer proposed another way to play chess to encourage more creative play.

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This form of the game – dubbed Chess960 – keeps the pawns in the same position but randomizes where the pieces at the back of the board – the knights, bishops, rooks, king and queen – are placed at the start while keeping the rest of the rules the same. It is named after the 960 starting positions that result from mixing it up at the back.

It was thought that Chess960 could allow for more permutations that would make the game fairer for both players. Yet research by physicist Marc Barthelemy at Paris-Saclay University suggests it’s not as simple as this.

Initial advantage

He used the open-source chess program called Stockfish to analyse each of the 960 starting positions and developed a statistical method to measure decision-making complexity by calculating how much “information” a player needs to identify the best moves.

He found that the standard game can be unfair, as players with black pieces who go second have to keep up with the moves from the player with white.

Yet regardless of starting positions at the back, Barthelemy discovered that white still has an advantage in almost all – 99.6% – of the 960 positions. He also found that the standard set-up – rook, knight, bishop, queen, king, bishop, knight, rook – is nothing special and is presumably an historical accident possibly as the starting positions are easy to remember, being visually symmetrical.

“Standard chess, despite centuries of cultural evolution, does not occupy an exceptional location in this landscape: it exhibits a typical initial advantage and moderate total complexity, while displaying above-average asymmetry in decision difficulty,” writes Barthelemy.

For a more fair and balanced match, Barthelemy suggests playing position #198, which has the starting positions as queen, knight, bishop, rook, king, bishop, knight and rook.

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Tetraquark measurements could shed more light on the strong nuclear force

Isabelle Dumé — Thu, 08 Jan 2026 10:00:25 +0000

Infrared visualization Wearable eyeglasses. (Courtesy: Fu et al., Sci. Adv. 12, eaed0245 (2026))

Most people can perceive different colours in the visible range of the electromagnetic spectrum – at wavelengths between about 400 and 700 nm. However, our eyes cannot see infrared radiation, let alone perceive infrared “colours”. But now a team at China’s Beijing Institute of Technology has created colloidal quantum dot-based light upconverters that convert the infrared to the visible while preserving the spectral notion of colour. These nanostructures can be incorporated into wearable eyeglasses and, more ambitiously, could someday be implanted directly into the retina.

Photoreceptors in mammalian eyes contain light-absorbing pigments consisting of opsins and their covalently linked retinals. Infrared light at wavelengths greater than 700 nm cannot be absorbed by these photoreceptors, so when such light reaches the retina no corresponding electric signal is sent to the brain. Seeing infrared radiation could reveal otherwise invisible features and improve night vision, which relies on infrared light.

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In recent years, researchers have made great strides in developing materials that capture photons with lower energies (in the infrared, for example) and re-emit them as photons with higher energies (typically visible or ultraviolet light). This process is known as upconversion, and the emitted light is said to be anti-Stokes shifted. This has led to the development of photoreceptor-binding upconversion nanoparticles that convert infrared light into visible emissions. These have been injected into mouse eyes and have been used to create wearable lenses for humans – with nonlinear upconversion projecting infrared-transformed visible light onto the cornea. While effective, these applications are limited to the narrow near-infrared (NIR) spectral range.

Confined electrons

Now, a team led by Ge Mu and Xin Tang studied a structure made up of semiconducting mercury telluride (HgTe) colloidal quantum dots (CQDs) atop an organic light-emitting diode (OLED). The OLED contains two light-emitting layers, one red-light-emitting and one cyan-light-emitting. Because of the small size of the CQDs, the electrons in them are confined in all three directions. This means that the electrons are restricted to discrete and separate atomic-like energy subbands rather than having access to a continuous band of allowed energies as they would in a bulk material.

When the CQDs absorb photons with infrared wavelengths, spanning the NIR to short-wave infrared regions, they produce excited carriers (electrons and holes) that then travel from their different energy levels into the OLED. This is a seamless process because the OLED is designed so that its electronic bands align with the sub-bands of the HgTe. When either the light intensity or the wavelength of the incident infrared light changes, explains Tang, the excited photocarriers are transported and recombined in the different emissive layers of the OLED thanks to the hole-trapping barriers that were engineered in these layers. The result is infrared-to-visible-light (red and cyan) upconversion.

Semi-transparent wearable eyeglasses

As a proof-of-concept, the researchers integrated their upconverter into lightweight, semi-transparent wearable eyeglasses and found that they can project multispectral infrared light onto the retina without affecting normal vision, so allowing the wearer to see infrared light as well as visible light. Indeed, a wearer can detect infrared light at wavelengths greater than 2 μm with a luminance of over 700 cd m⁻².

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Looking ahead, Tang says that the upconverter could be bound to light-sensitive proteins in the retina and so serve as an implantable next-generation retinal bionic photoreceptor. This structure would transform infrared light into visible light emissions that stimulate light-sensitive proteins on retinal neurons to bypass damaged photoreceptor cells and potentially restore visual function across both the visible and infrared.

This full colour upconverter has been a long-term project in my group, Tang tells Physics World. “Starting from an efficient single-colour upconverter, we then successfully demonstrated colour-tuneable OLEDs and Si-/Ge-/CMOS-integrated upconverters. And with our recent progress on the understanding of interfacial carrier transport between quantum dots and colour-tuneable OLEDs, we have now demonstrated this new full-colour upconverter.”

The latest work is detailed in Science Advances.

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Reinforcement learning could help airborne wind energy take off

Margaret Harris — Wed, 07 Jan 2026 16:00:12 +0000

Multinational missions Ariane 6 is the latest rocket in a long history of launchers – demonstrating the power of multinational co-operation for more than five decades. More than 3000 staff are working at ESA to implement space missions for exploring the universe, protecting our planet or serving our daily life. (Courtesy: ESA)

The European Space Agency (ESA) is globally recognized for its iconic space missions that push the boundaries of science and technology, whether it’s a rendezvous with a comet, landing a probe on Saturn’s giant moon Titan or mapping the stars of the Milky Way in unprecedented detail. But ESA does so much more than these headline-grabbing scientific and exploratory endeavours.

“Space is no longer solely a playground for curious minds,” says Eric Wille, ESA Head of the Opto-Electronics Section. “It’s really important for our everyday life too.” In fact, modern society relies on space technologies.

Project management The ESA Optical Ground Station in Tenerife is used to develop laser technologies for high-speed data links or quantum communication. The laser beam projects a guide star to control an adaptive optics system that improves the beam quality of the optical communication link. It is one of several ESA laboratories managed by Eric Wille and the opto-electronics section for testing optical systems for space. (Courtesy: ESA)

Satellite-based environmental monitoring, weather forecasting and global navigation are obvious examples, but there are many other important applications. For instance, the global financial system could not function without atomic clocks aboard satellites time-stamping millions of stock trades and digital payments every second. Similarly, when natural disasters strike, satellite networks become essential lifelines: mapping floods, tracking wildfires and helping with the co-ordination of emergency response efforts on the ground.

Fulfilling all of these roles and ESA’s bold space ambitions – from seeking answers to big questions about the universe to watching over our precious planet – requires a highly dedicated, technically proficient and multi-skilled workforce made up of scientists, engineers and various other professionals.

Diverse and challenging work

When Wille joined ESA as an optical systems engineer in 2009 after completing his PhD in experimental quantum optics, it was the sheer diversity of challenging work that attracted him. “Working in an international space agency, you’re partly a researcher, partly a project manager, partly also someone with ambassadorial skills,” he says. “That mixture is really something which I found at that time very attractive and I still like today, very much.”

Charlotte Pachot also craved a technically challenging role after her master in optics. She found it at Thales Alenia Space in France as a space engineer working on optical instruments. But after a few years, her interactions with ESA staff through joint projects convinced her to join the Agency as an optical engineer. She is now Lead Payload Engineer for the Laser Interferometer Space Antenna (LISA) mission, intended for launch in 2035, which will be the first gravitational wave detector in space.

Both Wille and Pachot have found that the technically challenging work at ESA is particularly satisfying because it has real-world impact. The first 10 years of Wille’s ESA career were largely spent on Athena (Advanced Telescope for High ENergy Astrophysics; now renamed NewAthena), a powerful X-ray observatory set to launch in the late 2030s that will provide fresh eyes on a wide range of hot and energetic processes in the universe.

Charlotte Pachot is overseeing the LISA optical bench assembly. Next to her is a model of LISA Pathfinder that tested critical technologies in space in 2016. (Courtesy: ESA)

In this role, Wille and the ESA team collaborated with an industrial consortium led by Dutch measuring instrument supplier cosine to develop a completely new type of optics, called silicon pore optics. Using techniques perfected by the semiconductor industry, cosine bonded and stacked many silicon plates on top of each other. By shaping the plates, a lightweight mirror to focus X-rays was created; in fact, 10 times lighter than the ones flying on current X-ray missions XMM-Newton and the Chandra X-ray Observatory.

Like Athena, LISA will also provide fresh eyes on cosmic events, but through the unique prism of gravitational waves. This will be achieved through a completely new approach involving a triangle of three satellites spaced 2.5 million kilometres apart.

Understandably, LISA calls for a unique optical bench, which Pachot is managing from design to manufacturing and testing. She sees her role as being like that of a conductor of an orchestra: a lot of her time is spent co-ordinating team members and partners, while also helping to solve technical, budget and schedule problems. For Pachot, tackling these daily friction points is part and parcel of working on real-world big science. “The instruments are very complex technically, very challenging, but they are also real pieces of hardware as part of a real project,” she says.

International community

As Wille and Pachot’s stories show, ESA selects talent from different career stages. The Agency offers several programmes that support students, graduates and experienced professionals in finding the right role for their profile and interests.

(Courtesy: ESA)" title="Click to open image in popup" href="https://physicsworld.com/wp-content/uploads/2026/08/2026-09-esa-nac-image04.jpg">

Device testing Lasers are used in many different space applications. Igniting launchers, high-speed optical communication, LIDARs for atmospheric measurements or for measuring gravity waves with LISA. The opto-electronics laboratory at ESTEC is frequently used to characterize the lifetime and performance of high-power diode lasers. (Courtesy: ESA)

For example, university students can benefit from ESA Academy sponsorship, such as participating in hands-on projects or training sessions. They can also join ESA as interns. Graduates can apply to ESA’s Graduate Trainee Programmes where they can gain experience on actual ESA projects and develop technical and professional skills. And for those currently in industry with less than three years’ experience, the Junior Professional Programme allows them to join ESA as staff members for four years and benefit from tailored learning and development opportunities to prepare them for a long-term position.

Whichever pathway they take, once new recruits get started in their first role, an excellent employment package – including competitive salary and pension scheme, hybrid working and flexible hours, and professional development training opportunities – comes as standard.

Eric Wille inspecting a new X-ray mirror using stacked silicon plates. The mirror was assembled using an automated stacking robot partially visible in the foreground. (Courtesy: ESA)

What sets ESA apart is the multicultural work environment. Team members might come from any of ESA’s 23 Member States and nine further Cooperating States and Associate Members. And recruits can be based in more than nine locations in seven countries (France, Germany, the Netherlands, Italy, Belgium, Spain and the UK). This makes for a melting pot of cultures.

“There’s a very lively expat community,” says Wille. “At the European Space Research and Technology Centre (ESTEC) and other big sites, it’s like a small Europe.” This cultural diversity is of course intentional. “The problems we have to solve require teamwork,” says Pachot. “And this is made easier at ESA because we all see problems in a different way depending on our culture.”

Working life at ESA

Want to learn more about working at ESA? Take a look at life at ESA and what ESA offers. Quickly find out which programme could be the best fit for you by following the pathways to ESA on this flowchart.

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Organic LED can electrically switch the handedness of emitted light

No Author — Wed, 07 Jan 2026 13:00:19 +0000

Circularly polarized (CP) light is encoded with information through its photon spin and can be utilized in applications such as low-power displays, encrypted communications and quantum technologies. Organic light emitting diodes (OLEDs) produce CP light with a left or right “handedness”, depending on the chirality of the light-emitting molecules used to create the device.

While OLEDs usually only emit either left- or right-handed CP light, researchers have now developed OLEDs that can electrically switch between emitting left- or right-handed CP light – without needing different molecules for each handedness.

“We had recently identified an alternative mechanism for the emission of circularly polarized light in OLEDs, using our chiral polymer materials, which we called anomalous circularly polarized electroluminescence,” says lead author Matthew Fuchter from the University of Oxford. “We set about trying to better understand the interplay between this new mechanism and the generally established mechanism for circularly polarized emission in the same chiral materials”.

Light handedness controlled by molecular chirality

The CP light handedness of an organic emissive molecule is controlled by its chirality. A chiral molecule is one that has two mirror-image structural isomers that can’t be superimposed on top of each other. Each of these non-superimposable molecules is called an enantiomer, and will absorb, emit and refract CP light with a defined spin angular momentum. Each enantiomer will produce CP light with a different handedness, through an optical mechanism called normal circularly polarized electroluminescence (NCPE).

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OLED designs typically require access to both enantiomers, but most chemical synthesis processes will produce racemic mixtures (equal amounts of the two enantiomers) that are difficult to separate. Extracting each enantiomer so that they can be used individually is complex and expensive, but the research at Oxford has simplified this process by using a molecule that can switch between emitting left- and right-handed CP light.

The molecule in question is a helical molecule called (P)-aza[6]helicene, which is the right-handed enantiomer. Even though it is just a one-handed form, the researchers found a way to control the handedness of the OLED, enabling it to switch between both forms.

Switching handedness without changing the structure

The researchers designed the helicene molecules so that the handedness of the light could be switched electrically, without needing to change the structure of the material itself. “Our work shows that either handedness can be accessed from a single-handed chiral material without changing the composition or thickness of the emissive layer,” says Fuchter. “From a practical standpoint, this approach could have advantages in future circularly polarized OLED technologies.”

Instead of making a structural change, the researchers changed the way that the electric charges are recombined in the device, using interlayers to alter the recombination position and charge carrier mobility inside the device. Depending on where the recombination zone is located, this leads to situations where there is balanced or unbalanced charge transport, which then leads to different handedness of CP light in the device.

When the recombination zone is located in the centre of the emissive layer, the charge transport is balanced, which generates an NCPE mechanism. In these situations, the helicene adopts its normal handedness (right handedness).

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However, when the recombination zone is located close to one of the transport layers, it creates an unbalanced charge transport mechanism called anomalous circularly polarized electroluminescence (ACPE). The ACPE overrides the NCPE mechanism and inverts the handedness of the device to left handedness by altering the balance of induced orbital angular momentum in electrons versus holes. The presence of these two electroluminescence mechanisms in the device enables it to be controlled electrically by tuning the charge carrier mobility and the recombination zone position.

The research allows the creation of OLEDs with controllable spin angular momentum information using a single emissive enantiomer, while probing the fundamental physics of chiral optoelectronics. “This work contributes to the growing body of evidence suggesting further rich physics at the intersection of chirality, charge and spin. We have many ongoing projects to try and understand and exploit such interplay,” Fuchter concludes.

The researchers describe their findings in Nature Photonics.

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Francis Crick: a life of twists and turns

No Author — Wed, 07 Jan 2026 11:00:48 +0000

Modern computation ranks among the great technical achievements of the 20th and 21st centuries and touches nearly every area of human activity. Today digital computing uses billions of transistors etched onto semiconducting silicon chips to work as tiny switches that represent binary 0 or 1. The technology underlies personal phones and laptop computers, and extends to supercomputers that perform nearly one quintillion operations per second (10¹⁸floating point operations per second, or FLOPS) and manipulate up to 100 petabytes of data.

Supercomputers can simulate otherwise intractable problems in science, from climate and weather patterns to protein folding and even black-hole interactions. However, further progress in scientific and general computation is approaching saturation because of fundamental limits, while the explosion in artificial intelligence (AI) based on large language models (LLMs) is clearly showing where computation needs to be improved. Physics is essential for this effort.

Nearing the physical limits

Back in 1965, Intel co-founder Gordon Moore famously predicted that the number of transistors we could fit onto a silicon chip would increase exponentially. He later forecasted that the number would double roughly every two years. Moore’s law has held for decades, albeit at a lower rate since the mid-2010s. More transistors meant increased computing power per chip, as well as faster computing.

That’s because smaller transistors switched between binary states more quickly, and higher transistor densities reduced the distance signals had to travel. These factors made it possible to increase “clock speed” – the frequency at which a computer’s central processing unit (CPU) synchronizes its internal operations – which helps determine computational speed. That frequency grew from tens to hundreds of megahertz in the 1970s–1990s until it reached gigahertz levels.

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But by the early 2000s, the increase in clock speed with density of transistors no longer held. Transistors that switched more frequently used more power, generating heat beyond what could easily be dissipated. Essentially, clock frequencies have stagnated at 3–5 GHz.

Within this limitation, the strategy for faster computing has been to design chips for parallel processing. Modern CPUs contain “cores”, which are separate processing units on a chip that independently read and execute instructions. In a CPU with four cores, each operates at the clock rate of 5 GHz, say; but since they operate in parallel, the throughput can approach a fourfold increase.

Another, more specialized form of parallel processing was introduced in graphics processing units (GPUs). While a CPU typically has between four and 32 powerful cores that have been optimized for flexibility in carrying out different tasks, a GPU has hundreds to thousands of simpler cores, designed to deal with many data elements for such tasks as rendering images or multiplying large matrices.

GPUs have become essential for supercomputers, but they also face limits. Trouble is, not all computational tasks can be broken into parallel operations, while adding more transistors to a chip still requires more power and generates yet more heat.

Large scales and rising costs

Supercomputer-level capabilities, however, are needed to support the rising use of LLMs such as ChatGPT, which are trained on huge data-sets and can create content based on natural language. Other LLMs followed, and by 2025 up to a billion individuals, corporations and governments were using AIs globally. This enormous scale of usage is highly demanding of computational and electrical power.

LLMs need two kinds of computation. First there is training computation, which analyses massive amounts of text from books, articles and websites containing trillions of tokens – words or parts of words. The training’s aim is for the model to learn statistical patterns in a given language, and estimate the probabilities for the next token in a given sequence.

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Training the largest LLMs can take up to 100,000 GPUs using tens to hundreds of megawatts, comparable to the biggest supercomputers. A few dozen of these centralized installations are estimated to be operating around the world, concentrated in the US and China.

The second type of computation is inference, where an already trained model responds to user prompts. Inference processing needs less computational and electrical power, but runs continuously to serve users. It must also respond with little latency, the time delay between request and response, so inference infrastructure is geographically distributed, not centralized.

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Of about 12,000 general data centres operating globally, hundreds to a few thousand now support a large AI cluster for inference, with the number rapidly growing. With this scale of continuous operation, inference is expected to dominate long-term AI energy use.

By 2030, global data centres, driven largely by AI, are expected to consume some 1000 TWh per year, corresponding to an average load of roughly 100 GW. This is a few percent of global electricity use and the resulting waste heat must be removed, requiring millions of gallons of water for some facilities. This heat discharge, along with the necessary additional electricity generation, will have a significant impact on the environment.

That’s provoked reactions to AI infrastructure, both from communities objecting to local data centres and governments concerned about national power grids. Scaling today’s relatively few specialized supercomputers to many large AI centres around the world carries significant costs, not to mention AI’s uncertain societal impact. As AI stretches resources, researchers are keen to rethink the very nature of computation.

Building a better bit

The use of electronic circuits to carry out binary logic, which defines modern computation, was mathematically formalized by the US mathematician Claude Shannon. In 1937 he showed that on/off electrical switches, arranged in what we now call a “logic gate” (based on the true/false logic George Boole invented in the 19th century), can carry out arithmetic as well as logical decision-making.

This approach has been embodied in computers, first using electromechanical relays, then vacuum tubes, followed by discrete transistors, and finally CMOS (complementary metal-oxide-semiconductors) integrated circuits. Each succeeding generation has slashed the energy required for a single binary switching event – for example, from nanojoules for an older discrete transistor to femtojoules for a transistor in a modern CMOS chip.

But this gain has been far outstripped by the rapidly growing volume of computation. Despite improved energy efficiency, our increasingly computerized world demands more electrical energy. Fortunately, there are other, more efficient ways to encode binary information using physical systems that support two stable states: the horizontal or vertical polarization of a photon; the up or down orientation of the spin magnetic moment of an electron; or persistent superconducting currents circulating in opposite directions.

Each approach has its own advantages and drawbacks. Photon-based computing offers high speed and reduced resistive heating; but it is difficult to store photons. Superconducting currents offer high speed, and require low energy per operation. But the energy cost for cryogenic cooling at 4 kelvin, hundreds of watts per one watt of heat removed, diminishes or wipes out the energy advantage.

“Spintronics” technology, however, has been the most successful of the three. Its basic device is the magnetic tunnel junction (MTJ), where a thin insulating barrier separates a “reference” and a “free” magnetic layer. The device’s electrical resistance depends on whether the magnetizations of the layers are parallel or antiparallel.

Universal memory Magnetoresistive random-access memory (MRAM) stores data in magnetic domains. Its main benefit is that it can retain data even when the power is turned off. (Courtesy: Shutterstock/luchschenF)

MTJs exist in hard disk drives and can also serve as read-write units in a magnetoresistive random-access memory (MRAM). To read, a small current is passed through the MTJ, and the resulting voltage shows the state of the bit. To write, a larger current is applied. The fixed layer polarizes the spin of the electrons, which carry angular momentum as they tunnel into the free layer.

This flips that layer’s magnetization, switching the magnetic bit, whose state survives even without power. That’s a key advantage of MRAMs compared to volatile CMOS RAMs, which require power and lose their stored data without it. MRAMs are not yet competitive with CMOS RAMs, but are already used in automotive, aerospace and other applications where their non-volatile nature is essential to reduce power needs and maintain their data under extreme conditions.

Along with this benefit, new possibilities for spintronics are emerging. In 2024 Nuh Gedik at the Massachussetts Institute of Technology (MIT) and colleagues reported that they had rapidly induced magnetism in iron phosphorus trisulfide with light (Nature 636 609). FePS₃ is an antiferromagnet where atomic spins in opposite directions result in little or no net magnetic field. The researchers found that picosecond pulses of terahertz light produced magnetic states that persisted for milliseconds – far longer than any other reported light-induced magnetism (see box below).

Metastable magnetization

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(Courtesy: Ilyas, B, Luo, T, von Hoegen, A et al. “Terahertz field-induced metastable magnetization near criticality in FePS₃” Nature 636 609 (2024) Springer Nature)

Shown here is the experimental set-up that an international team of physicists use to produce a long-lasting, light-driven magnetic state in a material such as iron phosphorus trisulfide (FePS₃), which becomes antiferromagnetic when cooled below about 118 K. They used an intense terahertz-frequency (THz) pulse (orange) to drive low-energy collective excitations, which induce transient changes in optical properties that can be probed with an 800 nm probe pulse (red). Fe²⁺ ions form a hexagonal lattice and their spins arrange ferromagnetically along the zig-zag chain (a-axis) and antiferromagnetically between the adjacent chains (the structure in the circle). The magnetic coupling between the layers is antiferromagnetic together with a small interlayer shear distortion along the a-axis. The THz pulses put the material in a metastable magnetic state that lasts for more than 2.5 milliseconds even after the light source is switched off.

Earlier this year, researchers at Beijing Normal University in China found that light-induced magnetic transitions consume little energy (ACS Nano 20 9051). If magnetic bits become competitive with electrical ones – activated by light or otherwise – they would unite working memory and long-term storage in one computational stage rather than two as we now have. Magnetic bits could also play a role in a bigger change in computer structure.

Bringing it all together

A novel form of computer architecture could also remove a famous bottleneck in computing that dates back to the influential 1945 proposal by the mathematician John von Neumann for a general computational design. He suggested using separate processing and memory (first put forth in 1837 by Charles Babbage for his mechanical “Analytical Engine”) but added the idea of the stored program.

By holding the instructions for computer operations in memory along with data, a computer program makes computation more flexible but has one big drawback. Data and instructions have to shuttle between processor and memory along the same channel, reducing computing throughput and using more energy than processing – the “von Neumann bottleneck”.

Novel computing: liquids, soft solids and deuterium

Financial flows London School of Economics economist AWH (Bill) Phillips with his eponymous machine, also known as the MONIAC analog computer, that modelled economic theory with water flows. (No known copyright restrictions, LSE Library archive)

At the heart of modern computing technology are ultra-pure silicon wafers. These nearly perfect regular crystalline solids form the substrates for integrated circuits, making it all the more surprising that less ordered materials – such as liquids and soft solids – have their own history in computation.

In 1949, for example, the UK-built Monetary National Income Analogue Computer (MONIAC) simulated the flow of money within a national economy using coloured water moving through transparent tubes under gravity. Water levels representing economic conditions were set by pumps and valves. As the water negotiated the system, it dynamically illustrated how parameters such as tax rate affect an entire economy, eventually settling into equilibrium.

Another liquid – mercury – also appeared in the early days of electronic computing. The first commercial unit in the US, UNIVAC I (1951), stored nine kilobytes of data as sound pulses continually recirculating in tubes filled with liquid mercury acting as delay lines. The units, which were bulky and heavy, provided serial rather than random access because the pulses travelled in sequence. Timing was crucial, and the mercury was held at a constant 40 °C to keep the speed of sound stable. Another early computer, EDVAC, also stored data in liquid mercury.

Since the 2000s researchers have shown that tiny droplets of oil, moving through small channels filled with water, can implement binary logic. If a droplet blocks a channel, a second droplet arriving behind it is diverted into another channel, representing a “decision”. Proper design can emulate the Boolean logic that underlies conventional computing. With channels only 100–200 µm across, microfluidic logic could route and process small samples, providing a lab on a chip for chemical analysis, biological research or medical diagnostics.

Yet another liquid – one more exotic than mercury – and a soft solid were apparently at least considered for computation in the same era as UNIVAC 1. According to Iain Dey and Douglas Buck’s 2017 biography The Cryotron Files: the Strange Death of a Pioneering Cold War Computer Scientist, the MIT scientist Dudley Buck once worked on a data storage system using magnetic pulses in liquid deuterium held at cryogenic temperature. In that Cold War era, US government money was available for any research that might help America and the authors describe how some of it also went on studies into a soft, wobbly foodstuff, lemon Jell-O as well as the viscous semi-liquid hair preparation Wildroot Creme Oil, which might also support sound waves in a memory unit. None of this Cold War research panned out, although at least the Jell-O experiments could treat the entire lab team to dessert.

One solution is to carry out processing and memory functions in the same physical element, potentially using a new type of electric circuit element originally proposed in 1971 by the US electrical engineer and computer scientist Leon Chua. Its resistance depends on the accumulated charge and, since charge is the time integral of current, therefore carries a memory of the device’s past electrical activity.

Chua dubbed his new element a memory resistor or “memristor” – and the concept can be used when a read-write MTJ holds a memory of past electrical activity as a magnetic bit. In 2026 Shahar Kvatinsky at the Israel Institute of Technology and colleagues showed that small MRAMs formed from MTJs can perform logical operations inside memory (Adv. Electron. Mater. 12 e00348).

In principle, therefore, this could also provide arithmetic processing inside memory, thereby removing the von Neumann bottleneck. The non-volatile memory would also save energy relative to CMOS memory. Problems remain though, such as reducing noise and producing large-scale MRAMs – but the ability to merge memory and computation within MRAMs has been established at small scales.

Certain material structures can also play a dual function. The wonder-material graphene – a 2D hexagonal lattice of carbon atoms – is electrically conductive when a voltage is applied in its plane, driving the electrons. If the graphene sheet is also placed between proton-conducting electrolytes, a second voltage applied across the sandwich produces a proton current (a flow of positive charge) perpendicular to the plane.

In 2024 Marcelo Lozada-Hidalgo at the University of Manchester and colleagues found that certain values of electron density in this structure make the graphene an insulator (Nature 630 619), producing a reversible change from conducting to insulating that forms a non-volatile two-state memory. Their set-up allowed the researchers to perform logic and memory operations in a single device for the first time.

As graphene, MRAMs, and other approaches are under study for in-memory computing, another method emulates a natural process – and is perhaps the biggest departure from conventional computing.

Dual purpose

(Courtesy: M Lozada-Hidalgo, Nature 630 619. CC BY 4.0)

(a) Graphene is well known to be a good electrical conductor, but in 2024 an international team of researchers used the 2D substance to make a new electrically-controlled switching device that supports both memory and logic functions. The device exploits graphene’s ability to conduct protons as well as electrons. The team showed that placing a sheet of it between proton-conducting electrolytes also produces a proton current perpendicular to the plane, with the proton and electron transport allowing independent control of field and charge density. Shown here are the top and bottom voltages and the direction of electron and proton flow. (b) Map of in-plane electronic conductance, σ_e, as a function of electric field E and charge density n. The left and bottom axes show that these variables are controlled by the difference and sum of the top and bottom electron voltages, respectively). (c) Map of proton transport current, I, as a function of E and n.

Copying biology

In the 1980s, Carver Mead – a Caltech physicist and engineer who had been instrumental in developing integrated circuits and deeply understood the physics of computing – made a radical proposal. Instead of building computers around centralized digital logic, we should instead design them to imitate the strategies that make the human brain highly efficient. He coined the term “neuromorphic” computing for this approach and is widely considered its founder.

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Using specific biological and biophysical features, the brain performs its cognitive and sensory tasks at the modest power of 20 watts. Its 86 billion neurons do not constantly use energy, but act sparsely in response to events, firing brief electrical spikes at definite timings and rates. A system like this can be expected to save energy compared to a conventional computer, which steadily consumes energy at the CPU clock rate.

Also, there is no von Neumann bottleneck in the brain. Information is stored as changes in synapses: the ~10¹⁴–10¹⁵connections among neurons that control signal flow. As a spike arrives, a synapse immediately applies its stored information. The modified signal is passed on to neurons that repeat the cycle. Storage and processing occur together within this closely linked 3D network, which also operates in a massively parallel manner.

Mead had envisioned an analogue neuromorphic design, but in practice the biological features are expressed digitally to match CMOS technology. For example, in 2017 Intel introduced its Loihi chip with event-driven spiking and closely connected computation and memory. A later model was reported in 2025 (arXiv:2503.18002) that trebled the throughput for matrix multiplication – the main computationally-intensive operation needed to train an LLM – with half the energy a standard GPU chip uses.

Similarly, in 2014 IBM built and tested a chip that emulated spiking behaviour, while a later version, dubbed NorthPole, does not use spiking. In 2025, meanwhile, IBM researchers reported that 288 linked NorthPole chips could carry out AI inference on certain sizes of language models at favourable speeds and power usage.

Chip off the old block Intel’s Loihi 2 chip is an example of a neuromorphic chip, based on how the human brain functions. With linked computation and memory, it can carry out AI inferencing considerably faster than standard chips, making it more energy efficient. (Courtesy: Walden Kirsch/Intel Corporation)

The future of computing and AI

Most of the novel approaches are in the proof-of-principle or pre-commercial phase and may never reach wide use, for both economic and engineering reasons. The investment in CMOS technology and the associated computer architecture is enormous. Any overall change would be a massive undertaking. Although a neuromorphic chip might be more efficient, it would require huge investment to be formally adopted by today’s markets and chip-making industry.

Even so, there are valuable lessons to be learned from the research into novel approaches – such as better integration of memory and computation. There is also a consensus that hybrid solutions can yield immediate benefits. An accelerator unit, such as a bank of neuromorphic chips, integrated with CMOS technology, could increase speed and decrease power use for the critical matrix multiplication stage. Upgrades like these can be included as new supercomputers and AI centres are being built, improving general and AI computation and reducing their energy costs.

We should also think of the problem from the other end: yes, we can now produce a form of AI based on LLMs. But this is ultimately a brute-force approach that demands a great deal of time, money and resources. It should continue to be refined, but there should also be space for bold ideas that may lead to better and more sustainable forms of AI, and of the computation it requires.

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Seven writers, four physicists, one room, lots of plushies

Robert P Crease — Wed, 19 Aug 2026 10:00:20 +0000

How many times have you wanted to throttle a journalist? Do you ever get incensed about articles, podcasts or videos that simplify, dumb down or belittle your research? Don’t you ever want to teach a science writer the basics?

Earlier this summer the US quantum physicist Christopher Fuchs got the chance. Thanks to some funding at the end of a grant cycle, Fuchs arranged a face-off between science journalists and writers, and a philosopher (me) at Royal Holloway, University of London. But the meeting wasn’t all about Fuchs having a big fat moan; he also gave the journalists the chance to push back.

Fuchs, who is from the University of Massachusetts, Boston, is the principal expositor of QBism, originally an acronym for “Quantum Bayesianism”, a research programme devoted to trying to figure out what the world must be like if quantum formalism is correct. But even top-flight writers, Fuchs thinks, get it wrong. And so emerged his idea for the workshop, called “Communicating QBism”.

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Attendees at the workshop, besides Fuchs himself, included his collaborator Rüdiger Schack from Royal Holloway – the gracious host of the meeting. There was also John DeBrota, who’s a postdoc at Ludwig Maximilian University, Munich, and Matthew Liefer, associate professor at the Institute for Quantum Studies at Chapman University, California.

The science writers were all experienced. One was Philip Ball, the author of some 30 books who has a PhD in physics and contributes regularly to Physics World. Jo Marchant, the sole female writer to attend, has a PhD in genetics and medical microbiology and is a New York Times bestselling author who recently wrote for New Scientist on QBism.

The four other writers were Robert Henderson, who has a PhD in quantum field theory; George Musser, who has a PhD in planetary science and is a contributing editor at Scientific American; Ulf von Rauchhaupt, a science editor at the Frankfurter Allgemeine Zeitung who has a PhD in extraterrestrial physics; and Zack Savitsky, a physics correspondent for Science.

I was invited at the last minute as a philosopher and writer who might find value in the event. I did.

Pugnacious and self-deprecating

Royal Holloway’s wooded campus on the western outskirts of London is dominated by the Founder’s Building, a beautifully ornate late-19th-century red-brick castle-like structure modelled on a French chateau with a central courtyard. But that’s only where we ate. Fuchs’s face-off, which took place on June 18–19, was holed in a modest modern science building down the hill.

Fuchs, whom I’ve met and written about several times, including for Physics World and a philosophy journal, is charmingly pugnacious. He approaches talks and conversations with unwavering zest and easily out-talks critics. He is relentless in pointing out even years-old mistakes to journalists and writers [editor’s note: I can confirm this]. Yet Fuchs can also be endearingly self-deprecating.

If you didn’t know Fuchs, you might be forgiven for thinking that he had an inquisition in mind. “I explain the ideas until I’m blue in the face,” the invitation ran, but you journalists are “pretty deficit in getting QBism right”. He continued, “What is it that makes QBism so damned hard to understand for journalists and the lay public?”

Fuchs then described himself as “communication impaired” – which was disingenuous. Based on Shack’s estimate, he’s sent about 150,000 QBism-related e-mails, he’s got “3 Million Miler” status from American Airlines thanks to his trips to give talks, and he was a lead speaker at the Helgoland conference on the centenary of quantum mechanics last year.

Some invitees were cautious, even sceptical. “QBism isn’t just another quantum physics interpretation”, Marchant replied to Fuchs’s invitation. “You’re challenging ideas of what physics is even about and requiring a radically different conception of what nature is”. Ball, meanwhile, perceptively reminded Fuchs that QBism is so novel that “the misrepresentations don’t just come from journalists”.

As for Musser, he warned Fuchs that the encounter may not be pleasant. “We will need to have free, open and frank discussions”, he responded, that may be “infuriating to you”. He counselled Fuchs to bring “plenty of plushy toys” for participants to safely throw at each other.

Fuchs’s invitation, however, also expressed warm and genuine respect for the coterie of science writers, who all agreed to come. Still, Fuchs brought a box of plushies just in case.

Speaking about science

On the meeting’s first day, the writers listened and learned. Schack opened the workshop by going over QBism’s vocabulary. “Probability” is not a property of things but refers to the expectations that an experimentalist has about outcomes of an action they are about to take. “Measurement” is that outcome.

“Quantum formalism”, meanwhile, is a tool that any experimentalist can use for making the best estimate they can about which outcome they will get. “Quantum states” are not properties of the world but compendia of probabilities to inform the agent about which actions they ought to take to achieve their goals.

Scene of the action Royal Holloway, University of London, was the venue for the stand-off between scientists and science journalists. (Courtesy: Robert P Crease)

After Schack, Fuchs gave a talk showing that QBism is neither a philosophical add-on to quantum theory nor something motivated by an attempt to resolve issues to do with entanglement, Bell inequality violations, and so on. Rather, QBism is the only satisfactory coherent account of what the world must be like if the quantum formalism is correct.

Fuchs quashed the idea that QBism is solipsistic; quantum formalisms, he pointed out, have been hammered out for a century and can be picked up by anyone as the best guide to their laboratory experience. He vented ire over stories that use the word “observe” and visual images to characterize what experimentalists do as if they were flies on the wall rather than actors in measurement events.

When Fuchs complained about a clause in an article by Savitsky which suggested such an interpretation, the writers cried “Foul!”. They accused Fuchs of “niggling” about a few words in a lengthy 4000-word article. When Fuchs replied, “I want to niggle over words!” he dodged a plushie.

Learning about writing

On the second day of the meeting, it was the scientists’ turn to listen and learn. Henderson talked about his struggle to “think like a QBist”, explaining how, during the Covid-19 pandemic, he joined Fuchs’s weekly Zoom sessions known as “QBukis”. These made him feel like he had come across “a more advanced civilization of aliens maybe, to whom premises I’d never thought to question were deemed antiquated and naïve”.

Henderson had an epiphany one day when he saw a bird hopping across his snow-covered lawn. The bird, he realized, was not a thing-in-itself but “the designation of a bundle of expectations” that he was bringing to bear to recognize it. What’s most challenging in learning to think like a QBist, Henderson concluded, is that QBism is “playing a different game than the rest of physics, or even science”.

Marchant followed with a talk entitled “Why QBism keeps getting misheard”, in which she showed a picture of a tennis player about to smash a rocketing tennis ball. What was happening, she said, wasn’t just body movements and ball trajectories – but a process of unfolding and continually updated predictions of actions.

QBism sees experimentalists like that tennis player, Marchant said, shepherding new events into the world, but it’s unintuitive to think that way. “QBism isn’t just another quantum physics interpretation,” Marchant said; “you’re challenging ideas of what physics is even about and requiring a radically different conception of what nature is and how we are related to it”. This, she concluded “is always going to be difficult”.

Ball pointed out that journalists are forced to keep in mind “mental attractors” that entice the public, journalists and even scientists to think in classical rather than quantum terms.

Between talks, the writers cited other constraints, such as time, money, audience and the space allotted by editors, all of which shape and dictate their output. Furthermore, writers are sometimes forced to use words whose meanings vary from their technical use.

At one point Fuchs showed a slide of Marchant’s New Scientist article and complained about the word “perspectives” in the standfirst. But Marchant and others objected that Fuchs’s “Gotcha!” play was again committing a foul; writers must lead readers gently into difficult stories with prose that sometimes must violate what researchers mean. “We have to write so people keep listening,” Marchant pointed out.

Impressed, Fuchs had to admit that he does something similar in his lectures, not leading with his most radical ideas but holding off until later.

One scientist then asked why writers don’t routinely run stories by sources before publication. Even if you accurately regurgitate the sources’ words, the writers replied, they often insist on changes, demand that their editors alter or retract the story, heap abuse on you, or even threaten to sue, causing the magazine to drop your article.

Tread carefully QBism is an alternative interpretation of quantum mechanics, but woe betide anyone whose explanation of it fails to live up to Christopher Fuchs’s standards. (Courtesy: Robert P Crease)

When a writer asked why scientists should even care about representations of their work in the media, the answers were difficult to synthesize. They ranged from the noble wish to nurture a scientifically literate public to the self-interested hope that good coverage might influence public perceptions and thus lead to more money from funding agencies.

But what’s hardest writing about QBism, explained the writers, has to do with Henderson’s “civilization of aliens” and Marchant’s “keep ‘em listening” points. Readers instinctively think, contra QBism, that the world has permanent residents and chiselled-in laws. The tennis player’s dive for the ball can always be reconstructed afterwards from a god’s-eye perspective in terms of classical physics, and it’s second-nature for both the public and even scientists to assume that the end of physics is to make such reconstructions.

The critical point

Years ago I wrote a column “The press is a foreign country” whose message was that communicating science is like engaging with another culture. Science and the media, I wrote, are separate institutions with different values, traditions and methods and reasons for seeking and justifying knowledge. The cross-cultural interaction, though, cannot always be made trouble-free, with all conflicts reconcilable by facilitators or relationship counsellors.

Given the qualifications of the participants at “Communicating QBism” – all but Zack had PhDs – one might have thought that the cross-cultural interaction at the workshop would be relaxed. It was, for the most part. But good scientific communication, it emerged, is not always a matter of clear explanations, demonstrations of relevance, dazzling imagery, or scientifically literate journalists.

Positive interactions may require constantly negotiating trade-offs between accuracy and comprehensibility, as well as setting up flinty encounters in which both scientists and writers actively hunt down and expose their own assumptions. These encounters must risk conflict and discomfort on both sides. Good science communication, in short, can use some genial pugilism, and Fuchs’s workshop was an excellent example.

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Physicists overcome ‘acoustic collapse’ to levitate multiple objects with sound

Isabelle Dumé — Wed, 07 Jan 2026 09:00:35 +0000

By analysing the signals from extragalactic fast radio bursts, astronomers at the Massachusetts Institute of Technology (MIT) say that the “missing matter” in the universe is distributed further away from galaxies than most theoretical simulations predict. Their finding – which is counterintuitive since the gravity from galaxies tends to pull everything closer to them – could help us better understand how highly energetic galactic activities, such as jets from supermassive black holes and explosions from old dying stars, impact the formation of cosmological structures.

“Ordinary” matter, which is built from atoms and their protons and neutrons (collectively known as baryons), makes up stars and galaxies and everything we see around us. However, the best models of the universe we have today suggest that close to 90% of this baryonic matter is “missing”.

The radio signals of FRBs are stretched

As their name implies, fast radio bursts (FRBs) are brief, intense bursts of radio waves spanning multiple wavelengths. They were first detected in 2007 and since then, astronomers have spotted thousands of others, including some within our own galaxy. They are thought to originate from cataclysmic processes involving compact celestial objects such as neutron stars and typically last a few milliseconds or even less. And these FRBs can be used to probe the missing baryonic matter.

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As they pass through the missing matter, the radio signals of FRBs are stretched (or “dispersed”) over time – that is, their overall duration becomes longer. The more missing matter they pass through, the more the signals are dispersed. The missing matter has an extremely low density – of just a single proton per cubic metre – so it is extremely difficult to identify, but researchers recently found that they could use the dispersion effect to detect it. In that previous study, they confirmed that intergalactic space, which contains most of the universe’s baryons, is home to tenuous clouds or filaments of diffuse plasma that make up the missing matter.

Data from CHIME and DESI

In the new work, a team led by astrophysicists Haochen Wang and Kiyoshi Masui has now gone a step further and mapped the extent to which this plasma extends. They did this by cross correlating the locations of millions of galaxies with the dispersion of nearly 3000 background FRBs on length scales of 0.1 to 50 Mpc.

The researchers used data from the Canadian Hydrogen Intensity Mapping Experiment (CHIME) catalogue and the Dark Energy Spectroscopic Instrument (DESI) survey. CHIME, a large radio telescope located in British Columbia, scans the entire northern sky for incoming radio waves and it can detect ultrashort, ultrabright radio signals. Indeed, it has detected about 4000 FRBs since it became operational. DESI, for its part, is an instrument mounted on the Mayall Telescope at Kitt Peak National Observatory, near Tucson, Arizona. It makes detailed measurements of the light coming from over 30 million galaxies – originally to provide estimates of dark energy, the mysterious force that is driving our universe’s expansion.

In all, the researchers detected 2870 FRB signals with CHIME and correlated these with the locations of around six million galaxies with DESI.

Missing baryonic matter scattered across a large radius

Their analyses revealed that on scales smaller than about 1 Mpc, the missing baryonic matter was indeed found around galaxies and galaxy clusters, but rather than being close to galaxies in a dense ball as expected, it was scattered across a large radius. “A galaxy is maybe a few 100,000 light years across, and we found missing matter out to about four million light years,” Masui says. “That’s further than the simulations predict.”

The new result backs up the idea that missing matter is projected out from a galaxy through highly energetic events, such as jets from supermassive black holes and explosions from old dying stars. These processes could be much more energetic than we think, note Wang and Masui, and they are stronger and much more violent.

The work, which is detailed in Physical Review Letters, proves that FRBs are a good way to study large-scale structures in the universe – in a similar way to how cosmologists have been using galaxies and the cosmic microwave background for decades, says Wang. “It has helped to establish FRBs as a new cosmological probe, especially for detecting the missing matter.”

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FRBs will only become a more popular tool in this context, he adds, especially given that several new radio telescopes, with upcoming surveys such as CHORD, DSA-2000 and the SKA, are being constructed around the world to offer much better FRB data in the coming years. “Indeed, we have already received more FRB data from our telescopes and are working on expanding our study,” Wang tells Physics World.

And that is not all: the researchers say they are also busy improving their analysis technique. “Until now, we have mostly examined the dispersion of FRBs but we are now working on extracting information from FRBs’ spatial positions relative to galaxies. This will reveal more details on how the missing matter is distributed in the universe.”

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When heat moves sideways

Lorna Brigham — Wed, 07 Jan 2026 08:30:17 +0000

Exceptional points occur in open physical systems where two or more resonances merge so completely that both their measured values and their underlying states become identical. (Technically speaking, the eigenvalues and the eigenvectors coalesce.) Exceptional points are different from ordinary degeneracies, where two frequencies may be the same but the corresponding states remain separate.

Near an exceptional point, a tiny change in the system can produce a relatively large change in the resonances. That is why exceptional points have been proposed for sensitive devices such as optical sensors. But there is a catch: a large response is not automatically useful if quantum noise also increases at the same time.

In a new paper, researchers Jan Wiersig and Stefan Rotter tackled this problem using quantum Fisher information. This is a quantity that sets the best possible precision of a measurement under ideal conditions.

Their approach treats the sensor as a scattering device, where incoming coherent light is transformed into outgoing light, and asks how much information about a small perturbation can be extracted from that change.

The results are, unsurprisingly, complicated – but that complexity turns out to be revealing.

For several years, different groups have reached seemingly contradictory conclusions about whether exceptional points actually improve sensing at the quantum limit, with some studies reporting a clear advantage and others finding none. Wiersig and Rotter’s analysis helps explain these disagreements: the answer depends on the physical assumptions and, in particular, on how the input light, losses and perturbation are matched to the resonant modes.

The analysis therefore does not yield a simple yes-or-no verdict. Under suitably matched conditions, exceptional points can provide substantially more quantum Fisher information. For example, a factor-of-four enhancement for a second-order exceptional point in a two-microring system, and an even larger enhancement in the third-order case.

What’s more, the optimum operating point need not be the exceptional point itself. Moving slightly away from it can produce linewidth splitting, creating a longer-lived mode that interacts more strongly with the perturbation and thereby increases the useful signal.

The take-home message is that exceptional points are not magic sensitivity boosters. They can provide an advantage when the light field, perturbation and resonant mode are well matched. Internal losses may weaken or remove this advantage, although small losses do not destroy the overall picture.

Future exceptional-point sensors will therefore need to be designed as complete measurement systems, rather than around the exceptional point alone.

Read the full article

Large thermal Hall effect in MnPS3

Mohamed Nawwar et al 2025 Rep. Prog. Phys. 88 080503

Fundamental limits of non-Hermitian sensing from quantum Fisher information – IOPscience

Jan Wiersig and Stefan Rotter 2026 Rep. Prog. Phys. 89 067501

Do you want to learn more about this topic?

Quantum-Hall physics and three dimensions Johannes Gooth, Stanislaw Galeski and Tobias Meng (2023)

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Symmetry‑preserving route to higher‑order insulators

Lorna Brigham — Wed, 07 Jan 2026 08:29:08 +0000

Topological insulators are materials that are insulating in the bulk within the bandgap, yet exhibit conductive states on their surface at frequencies within that same bandgap. These surface states are topologically protected, meaning they cannot be easily disrupted by local perturbations. In general, a material of n‑dimensions can host n‑1-dimensional topological boundary states. If the symmetry protecting these states is further broken, a bandgap can open between the n-1-dimensional states, enabling the emergence of n-2-dimensional topological states. For example, a 3D material can host 2D protected surface states, and breaking additional symmetry can create a bandgap between these surface states, allowing for protected 1D edge states. A material undergoing such a process is said to exhibit a phenomenon known as a higher-order topological insulator. In general, higher-order topological states appear in dimensions one lower than the parent topological phase due to the further unit-cell symmetry reduction. This requires at least a 2D lattice for second-order states, with the maximal order in 3D systems being three.

The researchers here introduce a new method for repeatedly opening the bandgap between topological states and generating new states within those gaps in an unbounded manner – without breaking symmetries or reducing dimensions. Their approach creates hierarchical topological insulators by repositioning domain walls between different topological regions. This process opens bandgaps between original topological states while preserving symmetry, enabling the formation of new hierarchical states within the gaps. Using one‑ and two‑dimensional Su–Schrieffer–Heeger models, they show that this procedure can be repeated to generate multiple, even infinite, hierarchical levels of topological states, exhibiting fractal-like behavior reminiscent of a Matryoshka doll. These higher-level states are characterized by a generalized winding number that extends conventional topological classification and maintains bulk-edge correspondence across hierarchies.

The researchers confirm the existence of second‑ and third-level domain‑wall and edge states and demonstrate that these states remain robust against perturbations. Their approach is scalable to higher dimensions and applicable not only to quantum systems but also to classical waves such as phononics. This broadens the definition of topological insulators and provides a flexible way to design complex networks of protected states. Such networks could enable advances in electronics, photonics, and phonon‑based quantum information processing, as well as engineered structures for vibration control. The ability to design complex, robust, and tunable hierarchical topological states could lead to new types of waveguides, sensors, and quantum devices that are more fault-tolerant and programmable.

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Chemical reactions are usually modelled as random, statistical events, with particles bumping into each other and rearranging according to energy and probability. But at extremely low temperatures, atoms and molecules can behave as coherent matter waves, meaning many particles share a common quantum phase. In this setting, a reaction can look less like classical chemistry and more like wave mixing in optics.

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In order to learn more about this phenomenon, a team of researchers from the University of Chicago studied a gas of caesium atoms, cooled down to 11nK to form a Bose–Einstein condensate.

Their approach was to use a Feshbach resonance to initiate the chemical reaction. This resonance is a way of using a magnetic field to tune how strongly ultracold atoms interact with each other.

At this point, two atoms can couple strongly to a bound molecular state, so pairs of atoms can be converted into weakly bound caesium diatomic molecules. Using this technique, they were able to transform an atomic Bose–Einstein condensate into a molecular Bose–Einstein condensate, consisting of about 10,000 molecules.

Their key result is the observation of phase doubling. This is the matter-wave version of phase matching in second harmonic generation, where two red photons in a nonlinear medium combine to produce one blue photon with twice the frequency and twice the momentum. Here, two atomic matter waves combine into a molecular matter wave whose phase is twice the atomic phase.

They also showed that molecules formed from atoms in different momentum states were enhanced beyond a classical expectation. This allowed the team to identify non-separable, entangled two-atom momentum states created during the reaction.

This work is one example of quantum many-body chemistry, where reactions are governed by the shared quantum phase of many atoms and molecules. This is also similar to how the direction of a Josephson supercurrent is determined by the phase difference across its junction.

Read the full article

Hierarchical topological states without dimension reduction

Joel R Pyfrom et al 2025 Rep. Prog. Phys. 88 118003

Observation of phase doubling and entanglement in coherent matter-wave reactions – IOPscience

Shu Nagata et al 2026 Rep. Prog. Phys. 89 060501

Do you want to learn more about this topic?

Interacting topological insulators: a review by Stephan Rachel (2018)

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New hybrid state of matter is a mix of solid and liquid

Isabelle Dumé — Tue, 06 Jan 2026 15:00:44 +0000

The boundary between a substance’s liquid and solid phases may not be as clear-cut as previously believed. A new state of matter that is a hybrid of both has emerged in research by scientists at the University of Nottingham, UK and the University of Ulm, Germany, and they say the discovery could have applications in catalysis and other thermally-activated processes.

In liquids, atoms move rapidly, sliding over and around each other in a random fashion. In solids, they are fixed in place. The transition between the two states, solidification, occurs when random atomic motion transitions to an ordered crystalline structure.

At least, that’s what we thought. Thanks to a specialist microscopy technique, researchers led by Nottingham’s Andrei Khlobystov found that this simple picture isn’t entirely accurate. In fact, liquid metal nanoparticles can contain stationary atoms – and as the liquid cools, their number and position play a significant role in solidification.

Some atoms remain stationary

The team used a method called spherical and chromatic aberration-corrected high-resolution transmission electron microscopy (Cc/Cs-corrected HRTEM) at the low-voltage SALVE instrument at Ulm to study melted metal nanoparticles (such as platinum, gold and palladium) deposited on an atomically thin layer of graphene. This carbon-based material acted a sort of “hob” for heating the particles, says team member Christopher Leist, who was in charge of the HRTEM experiments. “As they melted, the atoms in the nanoparticles began to move rapidly, as expected,” Leist says. “To our surprise, however, we found that some atoms remained stationary.”

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At high temperatures, these static atoms bind strongly to point defects in the graphene support. When the researchers used the electron beam from the transmission microscope to increase the number of these defects, the number of stationary atoms within the liquid increased, too. Khlobystov says that this had a knock-on effect on how the liquid solidified: when the stationary atoms are few in number, a crystal forms directly from the liquid and continues to grow until the entire particle has solidified. When their numbers increase, the crystallization process cannot take place and no crystals form.

“The effect is particularly striking when stationary atoms create a ring (corral) that surrounds and confines the liquid,” he says. “In this unique state, the atoms within the liquid droplet are in motion, while the atoms forming the corral remain motionless, even at temperatures well below the freezing point of the liquid.”

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Unprecedented level of detail

The researchers chose to use Cc/Cs-corrected HRTEM in their study because minimizing spherical and chromatic aberrations through specialized hardware installed on the microscope enabled them to resolve single atoms in their images.

“Additionally, we can control both the energy of the electron beam and the sample temperature (the latter using MEMS-heated chip technology),” Khlobystov explains. “As a result, we can study metal samples at temperatures of up to 800 °C, even in a molten state, without sacrificing atomic resolution. We can therefore observe atomic behaviour during crystallization while actively manipulating the environment around the metal particles using the electron beam or by cooling the particles. This level of detail under such extreme conditions is unprecedented.”

Effect could be harnessed for catalysis

The Nottingham-Ulm researchers, who report their work in ACS Nano, say they obtained their results by chance while working on an EPSRC-funded project on 1-2 nm metal particles for catalysis applications. “Our approach involves assembling catalysts from individual metal atoms, utilizing on-surface phenomena to control their assembly and dynamics,” explains Khlobystov. “To gain this control, we needed to investigate the behaviour of metal atoms at varying temperatures and within different local environments on a support material.

“We suspected that the interplay between vacancy defects in the support and the sample temperature creates a powerful mechanism for controlling the size and structure of the metal particles,” he tells Physics World. “Indeed, this study revealed the fundamental mechanisms behind this process with atomic precision.”

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The experiments were far from easy, he recalls, with one of the key challenges being to identify a thin, robust and thermally conductive support material for the metal. Happily, graphene meets all these criteria.

“Another significant hurdle to overcome was to be able to control the number of defect sites surrounding each particle,” he adds. “We successfully accomplished this by using the TEM’s electron beam not just as an imaging tool, but also as a means to modify the environment around the particles by creating defects.”

The researchers say they would now like to explore whether the effect can be harnessed for catalysis. To do this, Khlobystov says it will be essential to improve control over defect production and its scale. “We also want to image the corralled particles in a gas environment to understand how the phenomenon is influenced by reaction conditions, since our present measurements were conducted in a vacuum,” he adds.

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+ + + + https://physicsworld.com/?p=129863 + Researchers incorporate a heat blocking technology into the solar cells onboard remote uncrewed aerial vehicles

The post Semiconducting nanorods help laser-powered drones keep cool appeared first on Physics World.

A theoretical physicist’s journey through the food and drink industry

No Author — Tue, 06 Jan 2026 11:00:16 +0000

Rob Farr is a theorist and computer modeller whose career has taken him down an unconventional path. He studied physics at the University of Cambridge, UK, from 1991 to 1994, staying on to do a PhD in statistical physics. But while many of his contemporaries then went into traditional research fields – such as quantum science, high-energy physics and photonic technologies – Farr got a taste for the food and drink manufacturing industry. It’s a multidisciplinary field in which Farr has worked for more than 25 years.

After leaving academia in 1998, first stop was Unilever’s €13bn foods division. For two decades, latterly as a senior scientist, Farr guided R&D teams working across diverse lines of enquiry – “doing the science, doing the modelling”, as he puts it. Along the way, Farr worked on all manner of consumer products including ice-cream, margarine and non-dairy spreads, as well as “dry” goods such as bouillon cubes. There was also the occasional foray into cosmetics, skin creams and other non-food products.

As a theoretical physicist working in industrial-scale food production, Farr’s focus has always been on the materials science of the end-product and how it gets processed. “Put simply,” says Farr, “that means making production as efficient as possible – regarding both energy and materials use – while developing ‘new customer experiences’ in terms of food taste, texture and appearance.”

Ice-cream physics

One tasty multiphysics problem that preoccupied Farr for a good chunk of his time at Unilever is ice cream. It is a hugely complex material that Farr likens to a high-temperature ceramic, in the sense that the crystalline part of it is stored very near to the melting point of ice. “Equally, the non-ice phase contains fats,” he says, “so there’s all sorts of emulsion physics and surface science to take into consideration.”

Ice cream also has polymers in the mix, so theoretical modelling needs to incorporate the complex physics of polymer–polymer phase separation as well as polymer flow, or “rheology”, which contributes to the product’s texture and material properties. “Air is another significant component of ice cream,” adds Farr, “which means it’s a foam as well as an emulsion.”

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As well as trying to understand how all these subcomponents interact, there’s also the thorny issue of storage. After it’s produced, ice cream is typically kept at low temperatures of about –25 °C – first in the factory, then in transit and finally in a supermarket freezer. But once that tub of salted-caramel or mint choc chip reaches a consumer’s home, it’s likely to be popped in the ice compartment of a fridge freezer at a much milder –6 or –7 °C.

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Manufacturers therefore need to control how those temperature transitions affect the recrystallization of ice. This unwanted outcome can lead to phenomena like “sintering” (which makes a harder product) and “ripening” (which can lead to big ice crystals that can be detected in the mouth and detract from the creamy texture).

“Basically, the whole panoply of soft-matter physics comes into play across the production, transport and storage of ice cream,” says Farr. “Figuring out what sort of materials systems will lead to better storage stability or a more consistent product texture are non-trivial questions given that the global market for ice cream is worth in excess of €100bn annually.”

A shot of coffee?

After almost 20 years working at Unilever, in 2017 Farr took up a role as coffee science expert at JDE Peet’s, the Dutch multinational coffee and tea company. Switching from the chilly depths of ice cream science to the dark arts of coffee production and brewing might seem like a steep career phase change, but the physics of the former provides a solid bridge to the latter.

The overlap is evident, for example, in how instant coffee gets freeze-dried – a low-temperature dehydration process that manufacturers use to extend the shelf-life of perishable materials and make them easier to transport. In the case of coffee, freeze drying (or lyophilization, as it’s commonly known) also helps to retain flavour and aromas.

If you want to study a parameter space that’s not been explored before, the only way to do that is to simulate the core processes using fundamental physics
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After roasting and grinding the raw coffee beans, manufacturers extract a coffee concentrate using high pressure and water. This extract is then frozen, ground up and placed in a vacuum well below 0 °C. A small amount of heat is applied to sublime the ice away and remove the remaining water from the non-ice phase.

The quality of the resulting freeze-dried instant coffee is better than ordinary instant coffee. However, freeze-drying is also a complex and expensive process, which manufacturers seek to fine-tune by implementing statistical methods to optimize, for example, the amount of energy consumed during production.

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Such approaches involve interpolating the gaps between existing experimental data sets, which is where a physics mind-set comes in. “If you want to study a parameter space that’s not been explored before,” says Farr, “the only way to do that is to simulate the core processes using fundamental physics.”

Beyond the production line, Farr has also sought to make coffee more stable when it’s stored at home. Sustainability is the big driver here: JDE Peet’s has committed to make all its packaging compostable, recyclable or reusable by 2030. “Shelf-life prediction has been a big part of this R&D initiative,” he explains. “The work entails using materials science and the physics of mass transfer to develop next-generation packaging and container systems.”

Line of sight

After eight years unpacking the secrets of coffee physics at JDE Peet’s, Farr was given the option to relocate to the Netherlands in mid-2025 as part of a wider reorganization of the manufacturer’s corporate R&D function. However, he decided to stay put in Oxford and is now deciding between another role in the food manufacturing sector, or moving into a new area of research, such as nuclear energy, or even education.

Cool science “The whole panoply of soft-matter physics comes into play across the production, transport and storage of ice-cream,” says industrial physicist Rob Farr. (Courtesy: London Institute for Mathematical Sciences)

Farr believes he gained a lot from his time at JDE Peet’s. As well as studying a wide range of physics problems, he also benefited from the company’s rigorous approach to R&D, whereby projects are regularly assessed for profitability and quickly killed off if they don’t make the cut. Such prioritization avoids wasted effort and investment, but it also demands agility from staff scientists, who have to build long-term research strategies against a project landscape in constant flux.

A senior scientist needs to be someone who colleagues come to informally to discuss their technical challenges
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To thrive in that setting, Farr says collaboration and an open mind are essential. “A senior scientist needs to be someone who colleagues come to informally to discuss their technical challenges,” he says. “You can then find the scientific question which underpins seemingly disparate problems and work with colleagues to deliver commercially useful solutions.” For Farr, it’s a self-reinforcing dynamic. “As more people come to you, the more helpful you become – and I love that way of working.”

What Farr calls “line-of-sight” is another unique feature of industrial R&D in food materials. “Maybe you’re only building one span of a really long bridge,” he notes, “but when you can see the process end-to-end, as well as your part in it, that is a fantastic motivator.” Indeed, Farr believes that for physicists who want a job doing something useful, the physics of food materials makes a great career. “There are,” he concludes, “no end of intriguing and challenging research questions.”

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Quantum photonics network passes a scaling-up milestone

Isabelle Dumé — Tue, 06 Jan 2026 09:00:15 +0000

Step by step: A simplified schematic of the simulation framework, showing how circuit-level Pauli errors in noisy magic-state preparation protocols can be propagated and simplified using the underlying algebraic structure, reducing the problem to efficiently simulable logical Clifford errors acting on the output magic state. (Courtesy: Yousra Farhani)

Building a useful quantum computer is not simply a matter of adding more qubits. The greater challenge is making these qubits reliable enough to perform long computations without errors overwhelming the result. Quantum error correction addresses this problem by encoding each logical qubit across many physical ones, but it comes at a cost: many of the operations required for a general-purpose or “universal” quantum computer become highly resource intensive once fault-tolerant error correction is introduced.

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To address this resource challenge, researchers at the University of California, Davis, US have developed a classical simulation method that efficiently models the preparation of some of the most demanding quantum states. The method, which they describe in PRX Quantum, works even for large, high-fidelity protocols that were previously beyond reach.

Building a universal quantum computer

Logical operations in fault-tolerant (that is, error-corrected) quantum computing architectures fall into two broad categories. The first category is a set of operations known as Clifford gates that are relatively straightforward to implement and, importantly, can be simulated efficiently on a classical computer. By themselves, however, Clifford gates are not computationally universal. For that, you also need non-Clifford operations, which lie outside the set of classically-simulable gates and provide the missing ingredient for universal quantum computation.

To realize these non-Clifford operations in a fault-tolerant way, some qubits need to be in a special state known as a magic state. Preparing these magic states with sufficiently high fidelity is expected to dominate the cost of large-scale error-corrected quantum computers, so quantum computing theorists are searching intensively for more efficient preparation protocols. The problem is that this search contains a challenge of its own: how can we compare the efficiency of these approaches?

To assess a magic-state preparation protocol, we need to simulate it under realistic levels of error-inducing circuit-level noise. Yet the same non-Clifford operations that make magic states indispensable for quantum computation also make them difficult to simulate. Existing methods therefore become prohibitively expensive as protocols grow, limiting exact simulations to relatively small logical circuits.

Simplifying a difficult simulation

Rather than searching for a more efficient simulation algorithm directly, the UC Davis team of Samyak Surti, Lucas Daguerre and Isaac Kim first asked a more fundamental question: what mathematical structure do these protocols share?

Their framework for answering this question encompasses three broad classes of logical magic-state preparation protocols: code switching, magic state distillation, and Pauli-square-root Clifford (PSC) measurement-based protocols. In the first two classes, error propagation is relatively straightforward to analyse, but PSC protocols require a more sophisticated mathematical treatment. Rather than viewing these protocols simply as quantum circuits, Surti, Daguerre and Kim characterized their underlying algebraic structure, showing that Pauli errors (the fundamental types of qubit errors) propagate in a highly constrained and predictable way under sequential commutation. This commutation preserves the algebraic relationships between errors and logical operators, while anti-commuting operations exhibit predictable transformations rather than generating uncontrolled complexity.

These properties mean that commuting operations can be systematically reordered without changing the outcome, allowing much of the circuit’s complexity to be absorbed into its algebraic structure. Hence, rather than tracking an exponentially large quantum state, the simulator follows how a compact description of logical Pauli and Clifford errors evolves through the protocol.

The paper formalizes these ideas through a sequence of lemmas, propositions and theorems that establish the mathematical properties of PSC protocols. The result is a series of algorithms for simulating realistic, noisy, logical magic-state preparation protocols with a computational cost that scales polynomially with both the number of qubits and what is termed the stabilizer rank of the target magic state, which is a measure of its non-Clifford complexity. Since the standard single-qubit magic state has a stabilizer rank of only two, this complexity remains manageable even as the underlying error-correcting code grows, in marked contrast to state vector simulations that scale exponentially with qubit number. The team’s advance therefore makes large-scale logical simulations practical for the first time.

Accelerating fault-tolerant quantum computing

Although the new framework does not reduce the physical resources required to prepare logical magic states, it does change how those protocols can be analysed and designed. By exposing the algebraic structure underlying a broad class of logical magic-state preparation schemes, the UC Davis team transformed a computationally hard problem into one that admits efficient classical simulation. Researchers can therefore evaluate, compare and refine candidate preparation protocols under realistic circuit-level noise without resorting to exponentially expensive simulations or uncontrolled approximations.

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“The main motivation behind our work was to speed up the development of fault-tolerant quantum computer,” Kim tells Physics World. “I believe there is a large amount of uncertainty in how we will design and optimize magic state factories, which will likely remain as a bottleneck in the foreseeable future.”

As quantum computing progresses from proof-of-principle demonstrations to large-scale fault-tolerant architectures, the ability to characterize and benchmark logical operations efficiently will become increasingly important. This work offers more than just a faster simulator; instead, it provides a new theoretical foundation for designing one of the most resource-intensive building blocks of future quantum computers. “My hope is that this line of work can help us better design the fault-tolerant quantum computers we will be getting over the next few years,” Kim says.

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Band-aid like wearable sensor continuously monitors foetal movement

No Author — Mon, 05 Jan 2026 14:00:58 +0000

Multimodal monitoring Pressure and strain sensors on a clinical trial volunteer undergoing an ultrasound scan (left). Snapshot image of the ultrasound video recording (right). (Courtesy: Yap et al., Sci. Adv. 11 eady2661)

The ability to continuously monitor and interpret foetal movement patterns in the third trimester of a pregnancy could help detect any potential complications and improve foetal wellbeing. Currently, however, such assessment of foetal movement is performed only periodically, with an ultrasound exam at a hospital or clinic.

A lightweight, easily wearable, adhesive patch-based sensor developed by engineers and obstetricians at Monash University in Australia may change this. The patches, two of which are worn on the abdomen, can detect foetal movements such as kicking, waving, hiccups, breathing, twitching, and head and trunk motion.

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Reduced foetal movement can be associated with potential impairment in the central nervous system and musculoskeletal system, and is a common feature observed in pregnancies that end in foetal death and stillbirth. A foetus compromised in utero may reduce movements as a compensatory strategy to lower oxygen consumption and conserve energy.

To help identify foetuses at risk of complications, the Monash team developed an artificial intelligence (AI)-powered wearable pressure–strain combo sensor system that continuously and accurately detects foetal movement-induced motion in the mother’s abdominal skin. As reported in Science Advances, the “band-aid”-like sensors can discriminate between foetal and non-foetal movement with over 90% accuracy.

The system comprises two soft, thin and flexible patches designed to conform to the abdomen of a pregnant woman. One patch incorporates an octagonal gold nanowire-based strain sensor (the “Octa” sensor), the other is an interdigitated electrode-based pressure sensor.

Pressure and strain combo Photograph of the sensors on a pregnant mother (A). Exploded illustration of the foetal kicks strain sensor (B) and the pressure sensor (C). Dimensions of the strain (D) and pressure (E) sensors. (Courtesy: Yap et al., Sci. Adv. 11 eady2661)

The patches feature a soft polyimide-based flexible printed circuit (FPC) that integrates a thin lithium polymer battery and various integrated circuit chips, including a Bluetooth radiofrequency system for reading the sensor’s electrical resistance, storing data and communicating with a smartphone app. Each patch is encapsulated with kinesiology tape and sticks to the abdomen using a medical double-sided silicone adhesive.

The Octa sensor is attached to a separate FPC connector attached to the primary device, enabling easy replacement after each study. The pressure sensor is mounted on the silicone adhesive, to connect with the interdigitated electrode beneath the primary device. The Octa and pressure sensor patches are lightweight (about 3 g) and compact, measuring 63 x 30 x 4 mm and 62 x 28 x 2 mm, respectively.

Trialling the device

The researchers validated their foetal movement monitoring system via comparison with simultaneous ultrasound exams, examining 59 healthy pregnant women at Monash Health. Each participant had the pressure sensor attached to the area of their abdomen where they felt the most vigorous foetal movements, typically in the lower quadrant, while the strain sensor was attached to the region closest to foetal limbs. An accelerometer placed on the participant’s chest captured non-foetal movement data for signal denoising and training the machine-learning model.

Principal investigator Wenlong Cheng, now at the University of Sydney, and colleagues report that “the wearable strain sensor featured isotropic omnidirectional sensitivity, enabling detection of maternal abdominal [motion] over a large area, whereas the wearable pressure sensor offered high sensitivity with a small domain, advantageous for accurate localized foetal movement detection”.

The researchers note that the pressure sensor demonstrated higher sensitivity to movements directly beneath it compared with motion farther away, while the Octa sensor performed consistently across a wider sensing area. “The combination of both sensor types resulted in a substantial performance enhancement, yielding an overall AUROC [area under the receiver operating characteristic curve] accuracy of 92.18% in binary detection of foetal movement, illustrating the potential of combining diverse sensing modalities to achieve more accurate and reliable monitoring outcomes,” they write.

In a press statement, co-author Fae Marzbanrad explains that the device’s strength lies in a combination of soft sensing materials, intelligent signal processing and AI. “Different foetal movements create distinct strain patterns on the abdominal surface, and these are captured by the two sensors,” she says. “The machine-learning system uses the signals to detect when movement occurs while cancelling maternal movements.”

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The lightweight and flexible device can be worn by pregnant women for long periods without disrupting daily life. “By integrating sensor data with AI, the system automatically captures a wider range of foetal movements than existing wearable concepts while staying compact and comfortable,” Marzbanrad adds.

The next steps towards commercialization of the sensors will include large-scale clinical studies in out-of-hospital settings, to evaluate foetal movements and investigate the relationship between movement patterns and pregnancy complications.

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+ Has vacuum birefringence been seen at long last? + https://physicsworld.com/a/has-vacuum-birefringence-been-seen-at-long-last/ + Mon, 17 Aug 2026 11:00:24 +0000 + + + + https://physicsworld.com/?p=129809 + Polarized X-rays from magnetar could be first direct observation of quantum effect

The post Has vacuum birefringence been seen at long last? appeared first on Physics World.

Unlocking novel radiation beams for cancer treatment with upright patient positioning

No Author — Mon, 05 Jan 2026 12:27:49 +0000

Since the beginning of radiation therapy, almost all treatments have been delivered with the patient lying on a table while the beam rotates around them. But a resurgence in upright patient positioning is changing that paradigm. Novel radiation accelerators such as proton therapy, VHEE, and FLASH therapy are often too large to rotate around the patient, making access limited. By instead rotating the patient, these previously hard-to-access beams could now become mainstream in the future.

Join leading clinicians and experts as they discuss how this shift in patient positioning is enabling exploration of new treatment geometries and supporting the development of advanced future cancer therapies.

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L-R Serdar Charyyev, Eric Deutsch, Bill Loo, Rock Mackie

Novel beams covered and their representative speaker

Serdar Charyyev – Proton Therapy – Clinical Assistant Professor at Stanford University School of Medicine
-Eric Deutsch – VHEE FLASH – Head of Radiotherapy at Gustave Roussy
-Bill Loo – FLASH Photons – Professor of Radiation Oncology at Stanford Medicine
-Rock Mackie – Emeritus Professor at University of Wisconsin and Co-Founder and Chairman of Leo Cancer Care

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Ask me anything: Andrew Lamb – ‘Being flexible and curious matters far more than having everything mapped out from the beginning’

Tushna Commissariat — Mon, 05 Jan 2026 11:00:09 +0000

Be curious As CTO of a quantum tech company, Andrew Lamb values evidence-based decision making and being surrounded by experts. (Courtesy: Delta.g)

What skills do you use every day in your job?

A quantum sensor is a combination of lots of different parts working together in harmony: a sensor head containing the atoms and isolating them from the environment; a laser system to probe the quantum structure and manipulate atomic states; electronics to drive the power and timing of a device; and software to control everything and interpret the data. As the person building, developing and maintaining these devices you need to have expertise across all these areas. In addition to these skills, as the CTO my role also requires me to set the company’s technical priorities, determine the focus of R&D activities and act as the top technical authority in the firm.

In a developing field like quantum metrology, evidence-based decision making is crucial as you critically assess information, disregarding what is irrelevant and making an informed choice – especially when the “right answer” may not be obvious for months or even years. Challenges arise that may never have been solved before, and the best way to do so is to dive deep into the “why and how” something happens. Once the root cause is identified a creative solution then needs to be found; whether it is something brand new, or implementing an approach from an entirely different discipline.

What do you like best and least about your job?

The best thing about my job is the way in which it enables me to grow my knowledge and understanding of a wide variety of fields, while also providing me opportunities for creative problem solving. When you surround yourself with people who are experts in their field, there is no end to the opportunities to learn. Before co-founding Delta.g I was a researcher at the University of Birmingham where I learnt my technical skills. Moving into a start-up, we built a multidisciplinary team to address the operational, regulatory and technical barriers to establish a disruptive product in the marketplace. The diversity created within our company has afforded a greater pool of experts to learn from.

+ A laser-ranging technique has allowed physicists to measure the frame dragging of the Earth with an uncertainty approaching one part in a thousand, representing the highest precision yet for this parameter. The new result not only provides one of the most stringent confirmations of Einstein’s theory of general relativity in the near-Earth environment to date, it also sets stronger constraints on some alternative theories that have been put forward to explain the unsolved mystery of the universe’s accelerated expansion.

Frame dragging, also known as the dragging of inertial frames, is one of the predictions in Einstein’s theory of general relativity. Here, a massive, rotating object not only curves spacetime, it also drags it around as it rotates. The effect is very large around huge objects like black holes but is much smaller around Earth. It can be detected, however, by monitoring the motion of certain satellites in orbit around our planet.

There is a problem though in measuring the very tiny shift of the orbital plane around the Earth predicted by general relativity because the Earth is not a spherically symmetrical body, explains Ignazio Ciufolini of the Chinese Academy of Sciences, who led this new study. He and his colleagues overcame this difficulty by analysing motion data from the recently launched Laser Relativity Satellite 2 (LARES-2), developed by the Italian Space Agency, and its predecessor LAGEOS.

As the CTO, my role sits at the intersection of the technical and the commercial within the business. That means it is my responsibility to translate commercial milestones into a scientific plan, while also explaining our progress to non-experts. This can be challenging and quite stressful at times – particularly when I need to describe our scientific achievements in a way that truly reflects our advances, while still being accessible.

What do you know today that you wish you knew when you were starting out in your career?

For a long time, I didn’t know what direction I wanted to take, and I used to worry that the lack of a clear purpose would hold me back. Today I know that it doesn’t. Instead of fixating on finding a perfect path early on, it’s far more valuable to focus on developing skills that open doors. Whether those skills are technical, managerial or commercial, no knowledge is ever wasted. I’m still surprised by how often something I learned as far back as GCSE ends up being useful in my work now.

The combined orbits of these satellites act like a huge gyroscope and their position can be measured via laser ranging: a laser pulse is emitted towards the satellite and reflected back from the retroreflectors covering its surface. “By measuring the time it takes the laser light to come back, we can very precisely determine the position of the satellite,” says Ciufolini.

LARES-2 is a small, spherical satellite with a radius of 0.212 m and it is extremely heavy, weighing in at nearly 295 kg. Its orbit, he notes, is therefore perturbed only by the Earth’s gravitation and to a much lesser extent by non-gravitational effects, such as the push of the photons from the Sun and the Earth.

Removing the influence of Earth’s lunisolar tides

One of the difficult steps in the measurements, Ciufolini explains, was removing the influence of Earth’s lunisolar tides. These are the subtle distortions in the Earth’s gravity field caused by the tides raised by the Moon and Sun, which would otherwise hide the signal the researchers were looking for. “The most challenging part was to get rid of the orbital influence of Earth’s ‘K1 tide’, which biases the precision of the frame-dragging measurement,” he says.

“Thanks to this precise measurement, which is an order of magnitude better than previous Solar System measurements, we have been able to set stronger limits of validity to some theories alternative to general relativity proposed to possibly explain the great mystery of the accelerated expansion of the universe,” he tells Physics World. “Some of these theories predict something that may be related to quintessence (a mysterious time-dependent scalar field).”

While these theories predict the same so-called post-Newtonian weak-field effects as general relativity, they predict a different frame-dragging effect, he adds. Increasing the accuracy of frame-dragging (and indeed other tests of general relativity) can therefore place further limits on these other theories. It could also shed more light on phenomena like the flow of time around rotating black holes, where frame-dragging is extremely pronounced.

I also wish I had understood just how important it is to stay open to new opportunities. Looking back, every pivotal point in my career – switching from civil engineering to a physics degree, choosing certain undergraduate modules, applying for unexpected roles, even co-founding Delta.g – came from being willing to make a shift when an opportunity appeared. Being flexible and curious matters far more than having everything mapped out from the beginning.

The post Ask me anything: Andrew Lamb – ‘Being flexible and curious matters far more than having everything mapped out from the beginning’ appeared first on Physics World.

Laser-ranged satellites remain in orbit for many decades (LAGEOS was launched by NASA in 1976) and will carry on providing data for a very long time. “The more time we have, the more observational data we can obtain and therefore tests of general relativity (not only frame-dragging but also other tests) can be carried out with much increased precision,” says Ciufolini. “This data could also improve our knowledge of the Earth and allow, for example, improved determinations of the Earth tides and its centre of mass, which is useful for the Global Positioning System.”

The study is detailed in Nature.

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The environmental and climate cost of war

No Author — Fri, 02 Jan 2026 11:00:13 +0000

Despite not being close to the frontline of Russia’s military assault on Ukraine, life at the Ivano-Frankivsk National Technical University of Oil and Gas is far from peaceful. “While we continue teaching and research, we operate under constant uncertainty – air raid alerts, electricity outages – and the emotional toll on staff and students,” says Lidiia Davybida, an associate professor of geodesy and land management.

Last year, the university became a target of a Russian missile strike, causing extensive damage to buildings that still has not been fully repaired – although, fortunately, no casualties were reported. The university also continues to leak staff and students to the war effort – some of whom will tragically never return – while new student numbers dwindle as many school graduates leave Ukraine to study abroad.

Despite these major challenges, Davybida and her colleagues remain resolute. “We adapt – moving lectures online when needed, adjusting schedules, and finding ways to keep research going despite limited opportunities and reduced funding,” she says.

Resolute research

Davybida’s research focuses on environmental monitoring using geographic information systems (GIS), geospatial analysis and remote sensing. She has been using these techniques to monitor the devastating impact that the war is having on the environment and its significant contribution to climate change.

In 2023 she published results from using Sentinel-5P satellite data and Google Earth Engine to monitor the air quality impacts of war on Ukraine (IOP Conf. Ser.: Earth Environ. Sci. 1254 012112). As with the COVID-19 lockdowns worldwide, her results reveal that levels of common pollutants such as carbon monoxide, nitrogen dioxide and sulphur dioxide were, on average, down from pre-invasion levels. This reflects the temporary disruption to economic activity that war has brought on the country.

Wider consequences Ukrainian military, emergency services and volunteers work together to rescue people from a large flooded area in Kherson on 8 June 2023. Two days earlier, the Russian army blew up the dam of the Kakhovka hydroelectric power station, meaning about 80 settlements in the flood zone had to be evacuated. (Courtesy: Sergei Chuzavkov/SOPPA Images/Shutterstock)

More worrying, from an environment and climate perspective, were the huge concentrations of aerosols, smoke and dust in the atmosphere. “High ozone concentrations damage sensitive vegetation and crops,” Davybida explains. “Aerosols generated by explosions and fires may carry harmful substances such as heavy metals and toxic chemicals, further increasing environmental contamination.” She adds that these pollutants can alter sunlight absorption and scattering, potentially disrupting local climate and weather patterns, and contributing to long-term ecological imbalances.

A significant toll has been wrought by individual military events too. A prime example is Russia’s destruction of the Kakhovka Dam in southern Ukraine in June 2023. An international team – including Ukrainian researchers – recently attempted to quantify this damage by combining on-the-ground field surveys, remote-sensing data and hydrodynamic modelling; a tool they used for predicting water flow and pollutant dispersion.

The results of this work are sobering (Science 387 1181). Though 80% of the ecosystem is expected to re-establish itself within five years, the dam’s destruction released as much as 1.7 cubic kilometres of sediment contaminated by a host of persistent pollutants, including nitrogen, phosphorous and 83,000 tonnes of heavy metals. Discharging this toxic sludge across the land and waterways will have unknown long-term environmental consequences for the region, as the contaminants could be spread by future floods, the researchers concluded (figure 1).

1 Dam destruction

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(Reused with permission from Science 387 1181 10.1126/science.adn8655)

This map shows areas of Ukraine affected or threatened by dam destruction in military operations. Arabic numbers 1 to 6 indicate rivers: Irpen, Oskil, Inhulets, Dnipro, Dnipro-Bug Estuary and Dniester, respectively. Roman numbers I to VII indicate large reservoir facilities: Kyiv, Kaniv, Kremenchuk, Kaminske, Dnipro, Kakhovka and Dniester, respectively. Letters A to C indicate nuclear power plants: Chornobyl, Zaporizhzhia and South Ukraine, respectively.

Dangerous data

A large part of the reason for the researchers’ uncertainty, and indeed more general uncertainty in environmental and climate impacts of war, stems from data scarcity. It is near-impossible for scientists to enter an active warzone to collect samples and conduct surveys and experiments. Environmental monitoring stations also get damaged and destroyed during conflict, explains Davybida – a wrong she is attempting to right in her current work. Many efforts to monitor, measure and hopefully mitigate the environmental and climate impact of the war in Ukraine are therefore less direct.

In 2022, for example, climate-policy researcher Mathijs Harmsen from the PBL Netherlands Environmental Assessment Agency and international collaborators decided to study the global energy crisis (which was sparked by Russia’s invasion of Ukraine) to look at how the war will alter climate policy (Environ. Res. Lett. 19 124088).

They did this by plugging in the most recent energy price, trade and policy data (up to May 2023) into an integrated assessment model that simulates the environmental consequences of human activities worldwide. They then imposed different potential scenarios and outcomes and let it run to 2030 and 2050. Surprisingly, all scenarios led to a global reduction of 1–5% of carbon dioxide emissions by 2030, largely due to trade barriers increasing fossil fuel prices, which in turn would lead to increased uptake of renewables.

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But even though the sophisticated model represents the global energy system in detail, some factors are hard to incorporate and some actions can transform the picture completely, argues Harmsen. “Despite our results, I think the net effect of this whole war is a negative one, because it doesn’t really build trust or add to any global collaboration, which is what we need to move to a more renewable world,” he says. “Also, the recent intensification of Ukraine’s ‘kinetic sanctions’ [attacks on refineries and other fossil fuel infrastructure] will likely have a larger effect than anything we explored in our paper.”

Elsewhere, Toru Kobayakawa was, until recently, working for the Japan International Cooperation Agency (JICA), leading the Ukraine support team. Kobayakawa used a non-standard method to more realistically estimate the carbon footprint of reconstructing Ukraine when the war ends (Environ. Res.: Infrastruct. Sustain. 5 015015). The Intergovernmental Panel on Climate Change (IPCC) and other international bodies only account for carbon emissions within the territorial country. “The consumption-based model I use accounts for the concealed carbon dioxide from the production of construction materials like concrete and steel imported from outside of the country,” he says.

Using an open-source database Eora26 that tracks financial flows between countries’ major economic sectors in simple input–output tables, Kobayakawa calculated that Ukraine’s post-war reconstruction will amount to 741 million tonnes carbon dioxide equivalent over 10 years. This is 4.1 times Ukraine’s pre-war annual carbon-dioxide emissions, or the combined annual emissions of Germany and Austria.

However, as with most war-related findings, these figures come with a caveat. “Our input–output model doesn’t take into account the current situation,” notes Kobayakawa “It is the worst-case scenario.” Nevertheless, the research has provided useful insights, such as that the Ukrainian construction industry will account for 77% of total emissions.

“Their construction industry is notorious for inefficiency, needing frequent rework, which incurs additional costs, as well as additional carbon-dioxide emissions,” he says. “So, if they can improve efficiency by modernizing construction processes and implementing large-scale recycling of construction materials, that will contribute to reducing emissions during the reconstruction phase and ensure that they build back better.”

Military emissions gap

As the experiences of Davybida, Harmsen and Kobayakawa show, cobbling together relevant and reliable data in the midst of war is a significant challenge, from which only limited conclusions can be drawn. Researchers and policymakers need a fuller view of the environmental and climate cost of war if they are to improve matters once a conflict ends.

That’s certainly the view of Benjamin Neimark, who studies geopolitical ecology at Queen Mary University of London. He has been trying for some time to tackle the fact that the biggest data gap preventing accurate estimates of the climate and environmental cost of war is military emissions. During the 2021 United Nations Climate Change Conference (COP26), for example, he and colleagues partnered with the Conflict and Environment Observatory (CEOBS) to launch The Military Emissions Gap, a website to track and trace what a country accounts for as its military emissions to the United Nations Framework Convention on Climate Change (UNFCCC).

At present, reporting military emissions is voluntary, so data are often absent or incomplete – but gathering such data is vital. According to a 2022 estimate extrapolated from the small number of nations that do share their data, the total military carbon footprint is approximately 5.5% of global emissions. This would make the world’s militaries the fourth biggest carbon emitter if they were a nation.

The website is an attempt to fill this gap. “We hope that the UNFCCC picks up on this and mandates transparent and visible reporting of military emissions,” Neimark says (figure 2).

2 Closing the data gap

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(Reused with permission from Neimark et al. 2025 War on the Climate: A Multitemporal Study of Greenhouse Gas Emissions of the Israel–Gaza Conflict. Available at SSRN)

Current United Nations Framework Convention on Climate Change (UNFCCC) greenhouse-gas emissions reporting obligations do not include all the possible types of conflict emissions, and there is no commonly agreed methodology or scope on how different countries collect emissions data. In a recent publication War on the Climate: a Multitemporal Study of Greenhouse Gas Emissions of the Israel-Gaza Conflict, Benjamin Neimark et al. came up with this framework, using the UNFCCC’s existing protocols. These reporting categories cover militaries and armed conflicts, and hope to highlight previously “hidden” emissions.

Measuring the destruction

Beyond plugging the military emissions gap, Neimark is also involved in developing and testing methods that he and other researchers can use to estimate the overall climate impact of war. Building on foundational work from his collaborator, Dutch climate specialist Lennard de Klerk – who developed a methodology for identifying, classifying and providing ways of estimating the various sources of emissions associated with the Russia–Ukraine war – Neimark and colleagues are trying to estimate the greenhouse-gas emissions from the Israel–Gaza conflict.

Their studies encompass pre-conflict preparation, the conflict itself and post-conflict reconstruction. “We were working with colleagues who were doing similar work in Ukraine, but every war is different,” says Neimark. “In Ukraine, they don’t have large tunnel networks, or they didn’t, and they don’t have this intensive, incessant onslaught of air strikes from carbon-intensive F16 fighter aircraft.” Some of these factors, like the carbon impact of Hamas’ underground maze of tunnels under Gaza, seem unquantifiable, but Neimark has found a way.

“There’s some pretty good data for how big these are in terms of height, the amount of concrete, how far down they’re dug and how thick they are,” says Neimark. “It’s just the length we had to work out based on reported documentation.” Finding the total amount of concrete and steel used in these tunnels involved triangulating open-source information with media reports to finalize an estimate of the dimensions of these structures. Standard emission factors could then be applied to obtain the total carbon emissions. According to data from Neimark’s Confronting Military Greenhouse Gas Emissions report, the carbon emissions from construction of concrete infrastructure by both Israel and Hamas were more than the annual emissions of 33 individual countries and territories (figure 3).

3 Climate change and the Gaza war

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(Reused with permission from Neimark et al. 2024 Confronting Military Greenhouse Gas Emissions, Interactive Policy Brief, London, UK. Available from QMUL.)

Data from Benjamin Neimark, Patrick Bigger, Frederick Otu-Larbi and Reuben Larbi’s Confronting Military Greenhouse Gas Emissions report estimates the carbon emissions of the war in Gaza for three distinct periods: direct war activities; large-scale war infrastructure; and future reconstruction.

The impact of Hamas’ tunnels and Israel’s “iron wall” border fence are just two of many pre-war activities that must be factored in to estimate the Israel–Gaza conflict’s climate impact. Then, the huge carbon cost of the conflict itself must be calculated, including, for example, bombing raids, reconnaissance flights, tanks and other vehicles, cargo flights and munitions production.

Gaza’s eventual reconstruction must also be included, which makes up a big proportion of the total impact of the war, as Kobayakawa’s Ukraine reconstruction calculations showed. The United Nations Environment Programme (UNEP) has been systematically studying and reporting on “Sustainable debris management in Gaza” as it tracks debris from damaged buildings and infrastructure in Gaza since the outbreak of the conflict in October 2023. Alongside estimating the amounts of debris, UNEP also models different management scenarios – ranging from disposal to recycling – to evaluate the time, resource needs and environmental impacts of each option.

Visa restrictions and the security situation have prevented UNEP staff from entering the Gaza strip to undertake environmental field assessments to date. “While remote sensing can provide a valuable overview of the situation … findings should be verified on the ground for greater accuracy, particularly for designing and implementing remedial interventions,” says a UNEP spokesperson. They add that when it comes to the issue of contamination, UNEP needs “confirmation through field sampling and laboratory analysis” and that UNEP “intends to undertake such field assessments once conditions allow”.

The main risk from hazardous debris – which is likely to make up about 10–20% of the total debris – arises when it is mixed with and contaminates the rest of the debris stock. “This underlines the importance of preventing such mixing and ensuring debris is systematically sorted at source,” adds the UNEP spokesperson.

The ultimate cost

With all these estimates, and adopting a Monte Carlo analysis to account for uncertainties, Neimark and colleagues concluded that, from the first 15 months of the Israel–Gaza conflict, total carbon emissions were 32 million tonnes, which is huge given that the territory has a total area of just 365 km². The number also continues to rise.

Rubble and ruins Khan Younis in the Gaza Strip on 11 February 2025, showing the widespread damage to buildings and infrastructure. (Courtesy: Shutterstock/Anas Mohammed)

Why does this number matter? When lives are being lost in Gaza, Ukraine, and across Sudan, Myanmar and other regions of the world, calculating the environmental and climate cost of war might seem like something only worth bothering about when the fighting stops.

But doing so even while conflicts are taking place can help protect important infrastructure and land, avoid environmentally disastrous events, and to ensure the long rebuild, wherever the conflict may be happening, is informed by science. The UNEP spokesperson says that it is important to “systematically integrate environmental considerations into humanitarian and early recovery planning from the outset” rather than treating the environment as an afterthought. They highlight that governments should “embed it within response plans – particularly in areas where it can directly impact life-saving activities, such as debris clearance and management”.

With Ukraine still in the midst of war, it seems right to leave the final word to Davybida. “Armed conflicts cause profound and often overlooked environmental damage that persists long after the fighting stops,” she says. “Recognizing and monitoring these impacts is vital to guide practical recovery efforts, protect public health, prevent irreversible harm to ecosystems and ensure a sustainable future.”

The journal Environmental Research Letters has launched a Focus on Initial and Enduring Environmental Consequences of Armed Conflict, which is accepting authors’ expressions of interest until 28 February 2026.

The post The environmental and climate cost of war appeared first on Physics World.

Happy new year: what’s happening in physics in 2026?

Matin Durrani — Thu, 01 Jan 2026 00:15:57 +0000

I used to set myself the challenge every December of predicting what might happen in physics over the following year. Gazing into my imaginary crystal ball, I tried to speculate on the potential discoveries, the likely trends, and the people who might make the news over the coming year. It soon dawned on me that making predictions in physics is a difficult, if not futile, task

Apart from space missions pencilled in for launch on set dates, or particle colliders or light sources due to open, so much in science is simply unknown. That uncertainty of science is, of course, also its beauty; if you knew what was out there, looking for it wouldn’t be quite as much fun. So if you’re wondering what’s in store for 2026, I don’t know – you’ll just have to read Physics World to find out.

+ Having said that – and setting aside the insane upheaval going on in US science – this year’s Physics World Live series will give you some sense of what’s hot in physics right now, at least as far as we here at Physics World headquarters are concerned.

The first online panel discussion will be on quantum metrology – a burgeoning field that seeks to ensure companies and academics can test, validate and commercialize new quantum tech. Yes the International Year of Quantum Science and Technology officially ends with a closing ceremony in Ghana in February, but the impact of quantum physics will continue to reverberate throughout 2026.

You can also look forward to an online event on nuclear fusion, which offers a path to limitless energy and a potential solution to the climate crisis. But it’s a complex challenge and the route to commercialization is uncertain, despite lots of private firms being active in the area as a counterweight to the huge ITER experiment that’s being built in southern France. Among them is Tokamak Energy, which this year won a Business Award from the Institute of Physics (IOP).

Another of our online panels will be on medical physics, bringing together the current and two past editors-in-chief of Physics in Medicine & Biology. Published by IOP Publishing on behalf of the Institute of Physics and Engineering in Medicine, the journal turns 70 this year. The speakers will be reflecting on the vital role of medical-physics research to medicine and biology and examining how the field’s evolved since the journal was set up.

Medical physics will also be the focus of a new “impact project” in 2026 from the IOP, which will be starting another on artificial intelligence (AI) as well. The IOP will in addition be continuing its existing impact work on metamaterials, which were of course pioneered by – among others – the Imperial College theorist John Pendry. I wonder if a Nobel prize could be in store for him this year? That’s one prediction I’ll make that would be great if it came true.

Until then, on behalf of everyone at Physics World, I wish all readers – wherever you are – a happy and successful 2026. Your continued support is greatly valued.

The post Happy new year: what’s happening in physics in 2026? appeared first on Physics World.

+ +

Fancy some more? Check out our puzzles page.

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The quirkiest stories from the world of physics in 2025

Michael Banks — Wed, 31 Dec 2025 10:00:50 +0000

Shifting eastward (left) A map of Japan showing the epicentres of the main shock (Mw 9.0) and two strongest aftershocks (Mw 7.7 and 7.4) in the Tohoku-Oki earthquake. Each black dot represents a GNSS station. (right) The observed eastward components of ground motion at each of the GNSS sites from northeast (top) to southwest (bottom) of Japan are shown in black traces, with the shaded areas representing ground motion corresponding to the main shock and the aftershocks. (Courtesy: Sunyoung Park; motion data from P Xu et al. Earth, Planets and Space 71 43 2019)

A previously unrecognized source of seismic hazard caused parts of Japan to move eastwards by up to 5 mm within minutes of the 2011 Tohoku-Oki earthquake. Conventionally, such shifts occur when seismic waves generated by rupturing tectonic plates cause the plates to slip, triggering movements of the land mass and the ocean floor. But a new study finds that in the Tohoku-Oki quake, the real culprit was waves that travelled down to Earth’s core and back – a phenomenon more usually associated with efforts to image structures deep inside the Earth.

The 2011 Tohoku-Oki quake occurred at the boundary between the Pacific plate and the North American plate, with an offshore epicentre around 130 kilometres east of Sendai. At magnitude 9, it was one of the largest recorded earthquakes in history, and it caused widespread devastation, including thousands of fatalities. The tsunami that followed exacerbated this damage, with meltdowns of three out of six nuclear reactors at the Fukushima Daiichi power station releasing radioactive caesium into the air and water and prompting a large-scale evacuation with long-term health impacts.

The earthquake was bigger than most models estimated, which compelled seismologists to examine and revise existing models of the largest possible earthquakes and their frequencies in the boundaries of tectonic plates. Instrumented records of this earthquake are still revealing new information about geophysical processes in the boundaries of tectonic plates.

Surface to core and back

In the new work, researchers led by Sunyoung Park at the University of Chicago, US studied shear waves recorded following the earthquake in Japan’s dense network of high-rate Global Navigation Satellite System instruments. Along with the expected seismic waves from the earthquake rupture, the team found so-called ScS waves that travelled thousands of kilometres through the Earth, bounced off the core and travelled back to the surface, arriving across Japan almost simultaneously 13 minutes after the main shock. “The name ScS reflects that path: S[hear] through the mantle, c for reflection at the core-mantle boundary, and then S again on the return path,” Park explains.

Although seismologists have studied ScS waves extensively, they have mostly done so for the purpose of imaging the deep Earth. “Because [ScS waves] reflect from the core-mantle boundary, they have helped constrain the depth and properties of the core-mantle boundary; the structure of the lowermost mantle; attenuation and anisotropy in the mantle; and source characteristics of large earthquakes,” Park explains.

The team’s study offers the first evidence that ScS waves can also trigger significant displacement-causing slip after an earthquake, meaning that earthquake hazard researchers may need to consider these waves to fully capture consequences of earthquake ruptures on the land as well as deep within tectonic plates.

A high-quality, high-resolution dataset

Two aspects of the Tohoku-Oki earthquake made it an incredible opportunity to study the role of ScS waves in triggering a slip event. The first is the nature of the earthquake itself. As well as releasing tremendous amounts of energy, it occurred on a shallow tectonic fault that is dipping down. This combination sent strong shear wave energy travelling nearly vertically down to the core, generating ScS waves strong enough to trigger movement in the tectonic plates.

The second was the quality and resolution of data. “Because Japan is so densely instrumented, we can look for small, coherent signals that would likely be invisible elsewhere,” Park says. “This made it a natural case in which to ask whether delayed seismic phases might trigger additional deformation.”

Working with Hiroo Kanamori at the California Institute of Technology (Caltech), US, and Luis Rivera at the University of Strasbourg, France, Park considered whether Earth’s elastic response to the main shock could explain Japan’s 5-mm displacement. To better understand this possibility, they calculated displacements at all the instrumented locations for many possible configurations of the earthquake rupture. However, the results did not reproduce the observed eastward motion.

Competing models (left) Observed displacements in mm shown with coloured dots at each GNSS site across Japan. (right) The calculated displacement that would have occurred for slip only in the main shock area (orange dots), equal slip across the tectonic plates (light blue dots) and best fit slips corresponding to the observed displacement (dark blue dots). (Courtesy: Sunyoung Park)

The researchers then simulated possible slip scenarios across the tectonic plate interfaces, hoping to better characterize the levels and spatial extent of the slip that caused the eastward displacement. “The inferred slip event likely involved interfaces where the Pacific plate subducts beneath the Okhotsk Plate, and where the Philippine Sea plate subducts beneath the Eurasian plate,” Park says. Exactly how far this slip propagated, however, is still unknown because of the paucity of instrumented locations beyond Japan.

A slow-motion slip

Although the most memorable earthquakes and tsunamis are the ones that manifest havoc on Earth’s surface, the tectonic plates underneath are in perpetual but slow motion. At higher depths, these slow-moving plates produce earthquake events that unfold over days or weeks. Such events are called slow-slip or silent earthquakes and are important for accumulating and releasing stress as part of the earthquake cycle.

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Rather than triggering a fast earthquake rupture, the ScS waves from the Tohoku-Oki quake appear to have set off a slow slip event spread over a very large area at intermediate depths of 20–60 km. This is the depth range where seismologists commonly observe silent earthquakes, and it provides avenues for understanding the dynamic processes that impact the earthquake cycle. This continuous flux in Earth’s deeper layers is a source of curiosity for many seismologists, including Park.

“A broader motivation for me is a general interest in deep-shallow interaction in the Earth,” Park tells Physics World. “I am especially interested in cases where processes or wave propagation involving the deep interior can influence faulting and deformation in the shallow lithosphere or vice versa.”

The researchers report their findings in Science.

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Winning the popularity contest: the 10 most-read physics stories of 2025

Margaret Harris — Tue, 30 Dec 2025 15:00:15 +0000

Popularity isn’t everything. But it is something, so for the second year running, we’re finishing our trip around the Sun by looking back at the physics stories that got the most attention over the past 12 months. Here, in ascending order of popularity, are the 10 most-read stories published on the Physics World website in 2025.

10. Quantum on the brain

We’ve had quantum science on our minds all year long, courtesy of 2025 being UNESCO’s International Year of Quantum Science and Technology. But according to theoretical work by Partha Ghose and Dimitris Pinotsis, it’s possible that the internal workings of our brains could also literally be driven by quantum processes.

Though neurons are generally regarded as too big to display quantum effects, Ghose and Pinotsis established that the equations describing the classical physics of brain responses are mathematically equivalent to the equations describing quantum mechanics. They also derived a Schrödinger-like equation specifically for neurons. So if you’re struggling to wrap your head around complex quantum concepts, take heart: it’s possible that your brain is ahead of you.

9. Could an extra time dimension reconcile quantum entanglement with local causality?

Testing times A toy model from Marco Pettini seeks to reconcile quantum entanglement with Einstein’s theory of relativity. (Courtesy: Shutterstock/Eugene Ivanov)

Einstein famously disliked the idea of quantum entanglement, dismissing its effects as “spooky action at a distance”. But would he have liked the idea of an extra time dimension any better? We’re not sure he would, but that is the solution proposed by theoretical physicist Marco Pettini, who suggests that wavefunction collapse could propagate through a second time dimension. Pettini got the idea from discussions with the Nobel laureate Roger Penrose and from reading old papers by David Bohm, but not everyone is impressed by these distinguished intellectual antecedents. In this article, Bohm’s former student and frequent collaborator Jeffrey Bub went on the record to say he “wouldn’t put any money on” Pettini’s theory being correct. Ouch.

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8. And now for something completely different

Continuing the theme of intriguing, blue-sky theoretical research, the eighth-most-read article of 2025 describes how two theoretical physicists, Kaden Hazzard and Zhiyuan Wang, proposed a new class of quasiparticles called paraparticles. Based on their calculations, these paraparticles exhibit quantum properties that are fundamentally different from those of bosons and fermions. Notably, paraparticles strikes a balance between the exclusivity of fermions and the clustering tendency of bosons, with up to two paraparticles allowed to occupy the same quantum state (rather than zero for fermions or infinitely many for bosons). But do they really exist? No-one knows yet, but Hazzard and Wang say that experimental studies of ultracold atoms could hold the answer.

7. Shining a light on obscure Nobel prizes

Capturing colour A still life taken by Lippmann using his method sometime between 1890 and 1910. By the latter part of this period, the method had fallen out of favour, superseded by the simpler Autochrome process. (Courtesy: Photo in public domain)

The list of early Nobel laureates in physics is full of famous names – Roentgen, Curie, Becquerel, Rayleigh and so on. But if you go down the list a little further, you’ll find that the 1908 prize went to a now mostly forgotten physicist by the name of Gabriel Lippmann, for a version of colour photography that almost nobody uses (though it’s rather beautiful, as the photo shows). This article tells the story of how and why this happened. A companion piece on the similarly obscure 1912 laureate, Gustaf Dalén, fell just outside this year’s top 10; if you’re a member of the Institute of Physics, you can read both of them together in the November issue of Physics World.

6. How to teach quantum physics to everyone

Why should physicists have all the fun of learning about the quantum world? This episode of the Physics World Weekly podcast focuses on the outreach work of Aleks Kissinger and Bob Coecke, who developed a picture-driven way of teaching quantum physics to a group of 15-17-year-old students. One of the students in the original pilot programme, Arjan Dhawan, is now studying mathematics at the University of Durham, and he joined his former mentors on the podcast to answer the crucial question: did it work?

5. A great physicist’s Nobel-prize-winning mistake

Conflicting views Stalwart physicists Albert Einstein and Niels Bohr had opposing views on quantum fundamentals from early on, which turned into a lifelong scientific argument between the two. (Paul Ehrenfest/Wikimedia Commons)

Niels Bohr had many good ideas in his long and distinguished career. But he also had a few that didn’t turn out so well, and this article by science writer Phil Ball focuses on one of them. Known as the Bohr-Kramers-Slater (BKS) theory, it was developed in 1923 with help from two of the assistants/students/acolytes who flocked to Bohr’s institute in Copenhagen. Several notable physicists hated it because it violated both causality and the conservation of energy, and within two years, experiments by Walther Boethe and Hans Geiger proved them right. The twist, though, is that Boethe went on to win a share of the 1954 Nobel Prize for Physics for this work – making Bohr surely one of the only scientists who won himself a Nobel Prize for his good ideas, and someone else a Nobel Prize for a bad one.

4. Reconciling the ideas of Einstein and Newton

Black holes are fascinating objects in their own right. Who doesn’t love the idea of matter-swallowing cosmic maws floating through the universe? For some theoretical physicists, though, they’re also a way of exploring – and even extending – Einstein’s general theory of relativity. This article describes how thinking about black hole collisions inspired Jiaxi Wu, Siddharth Boyeneni and Elias Most to develop a new formulation of general relativity that mirrors the equations that describe electromagnetic interactions. According to this formulation, general relativity behaves the same way as the gravitational described by Isaac Newton more than 300 years ago, with the “gravito-electric” field fading with the inverse square of distance.

3. A list of the century’s best Nobel Prizes for Physics – so far

“Best of” lists are a real win-win. If you agree with the author’s selections, you go away feeling confirmed in your mutual wisdom. If you disagree, you get to have a good old moan about how foolish the author was for forgetting your favourites or including something you deem unworthy. Either way, it’s a success – as this very popular list of the top 5 Nobel Prizes for Physics awarded since the year 2000 (as chosen by Physics World editor-in-chief Matin Durrani) demonstrates.

2. Building bridges between gravity and quantum information theory

We’re back to black holes again for the year’s second-most-read story, which focuses on a possible link between gravity and quantum information theory via the concept of entropy. Such a link could help explain the so-called black hole information paradox – the still-unresolved question of whether information that falls into a black hole is retained in some form or lost as the black hole evaporates via Hawking radiation. Fleshing out this connection could also shed light on quantum information theory itself, and the theorist who’s proposing it, Ginestra Bianconi, says that experimental measurements of the cosmological constant could one day verify or disprove it.

1. The simplest double-slit experiment

Experiment schematic Two single atoms floating in a vacuum chamber are illuminated by a laser beam and act as the two slits. The interference of the scattered light is recorded with a highly sensitive camera depicted as a screen. Incoherent light appears as background and implies that the photon has acted as a particle passing only through one slit. (Courtesy: Wolfgang Ketterle, Vitaly Fedoseev, Hanzhen Lin, Yu-Kun Lu, Yoo Kyung Lee and Jiahao Lyu)

Back in 2002, readers of Physics World voted Thomas Young’s electron double-slit experiment “the most beautiful experiment in physics”. More than 20 years later, it continues to fascinate the physics community, as this, the most widely read article of any that Physics World published in 2025, shows.

Young’s original experiment demonstrated the wave-like nature of electrons by sending them through a pair of slits and showing that they create an interference pattern on a screen even when they pass through the slits one-by-one. In this modern update, physicists at the Massachusetts Institute of Technology (MIT), US, stripped this back to the barest possible bones.

Using two single atoms as the slits, they inferred the path of photons by measuring subtle changes in the atoms’ properties after photon scattering. Their results matched the predictions of quantum theory: interference fringes when they didn’t observe the photons’ path, and two bright spots when they did.

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It’s an elegant result, and the fact that the MIT team performed the experiment specifically to celebrate the International Year of Quantum Science and Technology 2025 makes its popularity with Physics World readers especially gratifying.

So here’s to another year full of elegant experiments and the theories that inspire them. Long may they both continue, and thank you, as always, for taking the time to read about them.

The post Winning the popularity contest: the 10 most-read physics stories of 2025 appeared first on Physics World.

+ New image captures glowing shock waves in the Helix Nebula + https://physicsworld.com/a/new-image-captures-glowing-shock-waves-in-the-helix-nebula/ + Fri, 14 Aug 2026 11:10:46 +0000 + + + + https://physicsworld.com/?p=129792 + Data were taken with the MOTHRA telescope, which is still under construction

The post New image captures glowing shock waves in the Helix Nebula appeared first on Physics World.

Exploring the icy moons of the solar system

No Author — Tue, 30 Dec 2025 11:00:45 +0000

Our blue planet is a Goldilocks world. We’re at just the right distance from the Sun that Earth – like Baby Bear’s porridge – is not too hot or too cold, allowing our planet to be bathed in oceans of liquid water. But further out in our solar system are icy moons that eschew the Goldilocks principle, maintaining oceans and possibly even life far from the Sun.

We call them icy moons because their surface, and part of their interior, is made of solid water-ice. There are over 400 icy moons in the solar system – most are teeny moonlets just a few kilometres across, but a handful are quite sizeable, from hundreds to thousands of kilometres in diameter. Of the big ones, the best known are Jupiter’s moons, Europa, Ganymede and Callisto, and Saturn’s Titan and Enceladus.

Yet these moons are more than just ice. Deep beneath their frozen shells – some –160 to –200 °C cold and bathed in radiation – lie oceans of water, kept liquid thanks to tidal heating as their interiors flex in the strong gravitational grip of their parent planets. With water being a prerequisite for life as we know it, these frigid systems are our best chance for finding life beyond Earth.

The first hints that these icy moons could harbour oceans of liquid water came when NASA’s Voyager 1 and 2 missions flew past Jupiter in 1979. On Europa they saw a broken and geologically youthful-looking surface, just millions of years old, featuring dark cracks that seemed to have slushy material welling up from below. Those hints turned into certainty when NASA’s Galileo mission visited Jupiter between 1995 and 2003. Gravity and magnetometer experiments proved that not only does Europa contain a liquid layer, but so do Ganymede and Callisto.

Meanwhile at Saturn, NASA’s Cassini spacecraft (which arrived in 2004) encountered disturbances in the ringed planet’s magnetic field. They turned out to be caused by plumes of water vapour erupting out of giant fractures splitting the surface of Enceladus, and it is believed that this vapour originates from an ocean beneath the moon’s ice shell. Evidence for an ocean on Titan is a little less certain, but gravity and radio measurements performed by Cassini and its European-built lander Huygens point towards the possibility of some liquid or slushy water beneath the surface.

Water, ice and JUICE

“All of these ocean worlds are going to be different, and we have to go to all of them to understand the whole spectrum of icy moons,” says Amanda Hendrix, director of the Planetary Science Institute in Arizona, US. “Understanding what their oceans are like can tell us about habitability in the solar system and where life can take hold and evolve.”

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To that end, an armada of spacecraft will soon be on their way to the icy moons of the outer planets, building on the successes of their predecessors Voyager, Galileo and Cassini–Huygens. Leading the charge is NASA’s Europa Clipper, which is already heading to Jupiter. Clipper will reach its destination in 2030, with the Jupiter Icy moons Explorer (JUICE) from the European Space Agency (ESA) just a year behind it. Europa is the primary target of scientists because it is possibly Jupiter’s most interesting moon as a result of its “astrobiological potential”. That’s the view of Olivier Witasse, who is JUICE project scientist at ESA, and it’s why Europa Clipper will perform nearly 50 fly-bys of the icy moon, some as low as 25 km above the surface. JUICE will also visit Europa twice on its tour of the Jovian system.

The challenge at Europa is that it’s close enough to Jupiter to be deep inside the giant planet’s magnetosphere, which is loaded with high-energy charged particles that bathe the moon’s surface in radiation. That’s why Clipper and JUICE are limited to fly-bys; the radiation dose in orbit around Europa would be too great to linger. Clipper’s looping orbit will take it back out to safety each time. Meanwhile, JUICE will focus more on Callisto and Ganymede – which are both farther out from Jupiter than Europa is – and will eventually go into orbit around Ganymede.

“Ganymede is a super-interesting moon,” says Witasse. For one thing, at 5262 km across it is larger than Mercury, a planet. It also has its own intrinsic magnetic field – one of only three solid bodies in the solar system to do so (the others being Mercury and Earth).

Beneath the icy exterior

It’s the interiors of these moons that are of the most interest to JUICE and Clipper. That’s where the oceans are, hidden beneath many kilometres of ice. While the missions won’t be landing on the Jovian moons, these internal structures aren’t as inaccessible as we might at first think. In fact, there are three independent methods for probing them.

Many layers A cross section of Jupiter’s moon Europa, showing its internal layering: a rocky core and ocean floor (possibly with hydrothermal vents), the ocean itself and the ice shell above. (Courtesy: NASA/JPL–Caltech)

If a moon’s ocean contains salts or other electrically conductive contaminants, interesting things happen when passing through the parent planet’s variable magnetic field. “The liquid is a conductive layer within a varying magnetic field and that induces a magnetic field in the ocean that we can measure with a magnetometer using Faraday’s law,” says Witasse. The amount of salty contaminants, plus the depth of the ocean, influence the magnetometer readings.

Then there’s radio science – the way that an icy moon’s mass bends a radio signal from a spacecraft to Earth. By making multiple fly-bys with different trajectories during different points in a moon’s orbit around its planet, the moon’s gravity field can be measured. Once that is known to exacting detail, it can be applied to models of that moon’s internal structure.

Perhaps the most remarkable method, however, is using a laser altimeter to search for a tidal bulge in the surface of a moon. This is exactly what JUICE will be doing when in orbit around Ganymede. Its laser altimeter will map the shape of the surface – such as hills and crevasses – but gravitational tidal forces from Jupiter are expected to cause a bulge on the surface, deforming it by 1–10 m. How large the bulge is depends upon how deep the ocean is.

“If the surface ice is sitting above a liquid layer then the tide will be much bigger because if you sit on liquid, you are not attached to the rest of the moon,” says Witasse. “Whereas if Ganymede were solid the tide would be quite small because it is difficult to move one big, solid body.”

As for what’s below the oceans, those same gravity and radio-science experiments during previous missions have given us a general idea about the inner structures of Jupiter’s Europa, Ganymede and Callisto. All three have a rocky core. Inside Europa, the ocean surrounds the core, with a ceiling of ice above it. The rock–ocean interface potentially provides a source of chemical energy and nutrients for the ocean and any life there.

Ganymede’s interior structure is more complex. Separating the 3400 km-wide rocky core and the ocean is a layer, or perhaps several layers, of high-pressure ice, and there is another ice layer above the ocean. Without that rock–ocean interface, Ganymede is less interesting from an astrobiological perspective.

Meanwhile, Callisto, being the farthest from Jupiter, receives the least tidal heating of the three. This is reflected in Callisto’s lack of evolution, with its interior having not differentiated into layers as distinct as Europa and Ganymede. “Callisto looks very old,” says Witasse. “We’re seeing it more or less as it was at the beginning of the solar system.”

Crazy cryovolcanism

Tidal forces don’t just keep the interiors of the icy moons warm. They can also drive dramatic activity, such as cryovolcanoes – icy eruptions that spew out gases and volatile materials like liquid water (which quickly freezes in space), ammonia and hydrocarbons. The most obvious example of this is found on Saturn’s Enceladus, where giant water plumes squirt out through “tiger stripe” cracks at the moon’s south pole.

But there’s also growing evidence of cryovolcanism on Europa. In 2012 the Hubble Space Telescope caught sight of what looked like a water plume jetting out 200 km from the moon. But the discovery is controversial despite more data from Hubble and even supporting evidence found in archive data from the Galileo mission. What’s missing is cast-iron proof for Europa’s plumes. That’s where Clipper comes in.

By Jove Three of Jupiter’s largest moons have solid water-ice. (Left) Europa, imaged by the JunoCam on NASA’s Juno mission to Jupiter. The surface sports myriad fractures and dark markings. (Middle) Ganymede, also imaged by the Juno mission, is the largest moon in our solar system. (Right) Our best image of ancient Callisto was taken by NASA’s Galileo spacecraft in 2001. The arrival of JUICE in the Jovian system in 2031 will place Callisto under much-needed scrutiny. (CC BY 3.0 NASA/JPL–Caltech/SwRI/MSS/ image processing by Björn Jónsson; CC BY 3.0 NASA/JPL–Caltech/SwRI/MSS/ image processing by Kalleheikki Kannisto; NASA/JPL/DLR)

“We need to find out if the plumes are real,” says Hendrix. “What we do know is if there is plume activity happening on Europa then it’s not as consistent or ongoing as is clearly happening at Enceladus.”

At Enceladus, the plumes are driven by tidal forces from Saturn, which squeeze and flex the 500 km-wide moon’s innards, forcing out water from an underground ocean through the tiger stripes. If there are plumes at Europa then they would be produced the same way, and would provide access to material from an ocean that’s dozens of kilometres below the icy crust. “I think we have a lot of evidence that something is happening at Europa,” says Hendrix.

These plumes could therefore be the key to characterizing the hidden oceans. One instrument on Clipper that will play an important role in investigating the plumes at Europa is an ultraviolet spectrometer, a technique that was very useful on the Cassini mission.

Because Enceladus’ plumes were not known until Cassini discovered them, the spacecraft’s instruments had not been designed to study them. However, scientists were able to use the mission’s ultraviolet imaging spectrometer to analyse the vapour when it was between Cassini and the Sun. The resulting absorption lines in the spectrum showed the plumes to be mostly pure water, ejected into space at a rate of 200 kg per second.

Ocean spray Geysers of water vapour loaded with salts and organic molecules spray out from the tiger stripes on Enceladus. (Courtesy: NASA/JPL/Space Science Institute)

The erupted vapour freezes as it reaches space and some of it snows back down onto the surface. Cassini’s ultraviolet spectrometer was again used, this time to detect solar ultraviolet light reflected and scattered off these icy particles in the uppermost layers of Enceladus’ surface. Scientists found that any freshly deposited snow from the plumes has a different chemistry from older surface material that has been weathered and chemically altered by micrometeoroids and radiation, and therefore a different ultraviolet spectrum.

Icy moon landing

Another two instruments that Cassini’s scientists adapted to study the plumes were the cosmic dust analyser, and the ion and neutral mass spectrometer. When Cassini flew through the fresh plumes and Saturn’s E-ring, which is formed from older plume ejections, it could “taste” the material by sampling it directly. Recent findings from this data indicate that the plumes are rich in salt as well as organic molecules, including aliphatic and cyclic esters and ethers (carbon-bonded acid-based compounds such as fatty acids) (Nature Astron. 9 1662). Scientists also found nitrogen- and oxygen-bearing compounds that play a role in basic biochemistry and which could therefore potentially be building blocks of prebiotic molecules or even life in Enceladus’ ocean.

Blue moon Enceladus, as seen by Cassini in 2006. The tiger stripes are the blue fractures towards the south. (Courtesy: NASA/JPL/Space Science Institute)

While Cassini could only observe Enceladus’ plumes and fresh snow from orbit, astronomers are planning a lander that could let them directly inspect the surface snow. Currently in the technology development phase, it would be launched by ESA sometime in the 2040s to arrive at the moon in 2054, when winter at Enceladus’ southern, tiger stripe-adorned pole turns to spring and daylight returns.

“What makes the mission so exciting to me is that although it looks like every large icy moon has an ocean, Enceladus is one where there is a very high chance of actually sampling ocean water,” says Jörn Helbert, head of the solar system section at ESA, and the science lead on the prospective mission.

The planned spacecraft will fly through the plumes with more sophisticated instruments than Cassini’s, designed specifically to sample the vapour (like Clipper will do at Europa). Yet adding a lander could get us even closer to the plume material. By landing close to the edge of a tiger stripe, a lander would dramatically increase the mission’s ability to analyse the material from the ocean in the form of fresh snow. In particular, it would look for biosignatures – evidence of the ocean being habitable, or perhaps even inhabited by microbes.

However, new research urges caution in drawing hasty conclusions about organic molecules present in the plumes and snow. While not as powerful as Jupiter’s, Saturn also has a magnetosphere filled with high-energy ions that bombard Enceladus. A recent laboratory study, led by Grace Richards of the Istituto Nazionale di Astrofisica e Planetologia Spaziale (IAPS-INAF) in Rome, found that when these ions hit surface-ice they trigger chemical reactions that produce organic molecules, including some that are precursors to amino acids, similar to what Cassini tasted in the plumes.

So how can we be sure that the organics in Enceladus’ plumes originate from the ocean, and not from radiation-driven chemistry on the surface? It is the same quandary for dark patches around cracks on the surface of Europa, which seem to be rich with organic molecules that could either originate via upwelling from the ocean below, or just from radiation triggering organic chemistry. A lander on Enceladus might solve not just the mystery of that particular moon, but provide important pointers to explain what we’re seeing on Europa too.

More icy companions

Enceladus is not Saturn’s only icy moon; there’s Titan too. As the ringed planet’s largest moon at 5150 km across, Titan (like Ganymede) is larger than Mercury. However, unlike the other moons in the solar system, Titan has a thick atmosphere rich in nitrogen and methane. The atmosphere is opaque, hiding the surface from spacecraft in orbit except at infrared wavelengths and radar, which means that getting below the smoggy atmosphere is a must.

ESA did this in 2005 with the Huygens lander, which, as it parachuted down to Titan’s frozen surface, revealed it to be a land of hills and dune plains with river channels, lakes and seas of flowing liquid hydrocarbons. These organic molecules originate from the methane in its atmosphere reacting with solar ultraviolet.

Until recently, it was thought that Titan has a core of rock, surrounded by a shell of high-pressure ice, above which sits a layer of salty liquid water and then an outer crust of water ice. However, new evidence from re-analysing Cassini’s data suggests that rather than oceans of liquid water, Titan has “slush” below the frozen exterior, with pockets of liquid water (Nature 648 556). The team, led by Flavio Petricca from NASA’s Jet Propulsion Laboratory, looked at how Titan’s shape morphs as it orbits Saturn. There is a several-hour lag between the moon passing the peak of Saturn’s gravitational pull and its shape shifting, implying that while there must be some form of non-solid substance below Titan’s surface to allow for deformation, more energy is lost or dissipated than would be if it was liquid water. Instead, the researchers found that a layer of high-pressure ice close to its melting point – or slush – better fits the data.

Hello halo Titan is different to other icy moons in that it has a thick atmosphere, seen here with the moon in silhouette. (Courtesy: NASA/JPL/Space Science Institute)

To find out more about Titan, NASA is planning to follow in Huygens’ footsteps with the Dragonfly mission but in an excitingly different way. Set to launch in 2028, Dragonfly should arrive at Titan in 2034 where it will deploy a rotorcraft that will fly over the moon’s surface, beneath the smog, occasionally touching down to take readings. Scientists are intending to use Dragonfly to sample surface material with a mass spectrometer to identify organic compounds and therefore better assess Titan’s biological potential. It will also perform atmospheric and geological measurements, even listening for seismic tremors while landed, which could provide further clues about Titan’s interior.

Jupiter and Saturn are also not the only planets to possess icy moons. We find them around Uranus and Neptune too. Even the dwarf planet Pluto and its largest moon Charon have strong similarities to icy moons. Whether any of these bodies, so far out from the Sun, can maintain an ocean is unclear, however.

Recent findings point to an ocean deep inside Uranus’ moon Ariel that may once have been 170 km deep, kept warm by tidal heating (Icarus 444 116822). But over time Ariel’s orbit around Uranus has become increasingly circular, weakening the tidal forces acting on it, and the ocean has partly frozen. Another of Uranus’ moons, Miranda, has a chaotic surface that appears to have melted and refrozen, and the pattern of cracks on its surface strongly suggests that the moon also contains an ocean, or at least did 150 million years ago. A new mission to Uranus is a top priority in the US’s most recent Decadal Review.

It’s becoming clear that icy ocean moons could far outnumber more traditional habitable planets like Earth, not just in our solar system, but across the galaxy (although none have been confirmed yet). Understanding the internal structures of the icy moons in our solar system, and characterizing their oceans, is vital if we are to expand the search for life beyond Earth.

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Particle and nuclear physics: quirky favourites from 2025

Hamish Johnston — Mon, 29 Dec 2025 11:19:22 +0000

Particle and nuclear physics evokes evokes images of huge accelerators probing the extremes of matter. But in this round-up of my favourite research of 2025 I have chosen five stories in which particle and nuclear physics forms the basis for a range of quirky and fascinating research from astrophysics to archaeology.

CERN experiment sheds light on missing blazar radiation

Stable discovery The Fireball experiment installed in the HiRadMat irradiation area at CERN. (Courtesy: Gianluca Gregori)

My first pick involves simulating the vast cosmic plasma in the lab. Blazars are extremely bright galaxies that are powered by supermassive black holes. They emit intense jets of radiation, including teraelectronvolt gamma rays – which can be detected by astronomers if a jet happens to point at Earth. As these high-energy photons travel through intergalactic space, they interact with background starlight, producing numerous electron–positron pairs. These pairs should, in theory, generate gigaelectronvolt gamma rays – but this secondary radiation has never been observed. One explanation is that intergalactic magnetic fields deflect these pairs and the resulting gamma rays away from our line of sight. However, there is no conclusive evidence for such fields. Another theory is that plasma instabilities in the sparse intergalactic medium could dissipate the energy of the pair beams. Now, physicists working on the Fireball experiment at CERN have simulated the effect of plasma instabilities by firing a beam of electron–positron pairs through a metre-long argon plasma. They found that plasma instabilities are too weak to account for the missing gamma radiation – strengthening the case for the existence of primordial intergalactic magnetic fields.

Portable source could produce high-energy muon beams

A compact source of muons could soon be discovering hidden chambers in ancient pyramids. Muons are subatomic particles similar to electrons but 200 times heavier. They are produced in copious amounts in the atmosphere by cosmic rays. These cosmic muons can penetrate long distances into materials and are finding increasing use in “muon tomography” – a technique that has imaged the interiors of huge objects such as volcanoes, pyramids and nuclear reactors. One downside of muon tomography is that muons are always vertically incident, limiting opportunities for imaging. While beams of muons can be made in accelerators, these are large and expensive facilities – and the direction of such beams are also fixed. Now, physicists at Lawrence Berkeley National Laboratory have demonstrated a compact, and potentially portable method for generating high-energy muon beams using laser plasma acceleration. It uses an ultra-intense, tightly focused laser pulse to accelerate electrons in a short plasma channel. These electrons then strike a metal target creating a muon beam. With more work, compact and portable muon sources could be developed, leading to new possibilities for non-destructive imaging in archaeology, geology, and nuclear safety.

Radioactive BEC could be a ‘superradiant neutrino laser’

Could a “superradiant neutrino laser” be created using radioactive atoms in an ultracold Bose–Einstein condensate (BEC)? The answer is “maybe”, according to theoretical work by two physicists in the US. Their proposal involves creating a BEC of rubidium-83, which undergoes beta decay involving the emission of neutrinos. Unlike photons, neutrinos are fermions and therefore cannot form the basis of conventional laser. However, if the atoms in the BEC are close enough together, quantum interactions between the atomic nuclei could accelerate beta decay and create a coherent, laser-like burst of neutrinos. This is a well-known phenomenon called superradiance. While the idea could be tested using existing technologies for making BECs, it would be a challenge to deploy radioactive rubidium in a conventional atomic physics lab. Another drawback is that there are no obvious applications for a neutrino laser – at least for now. However, the very idea of a neutrino laser is so cool that I am hoping that someone will try to build one soon!

Antimatter could be transported by road

Lifted by crane The BASE-STEP system is moved to a lorry at CERN. Marcel Leonhardt (right), physicist at HHU, checks the status of the device and confinement of the protons on a tablet. (Courtesy: BASE/Julia Jäger)

If you happen to be driving between Geneva and Dusseldorf in the future, you might just overtake a shipment of antimatter. It will be on its way to an experiment that could solve some of the biggest mysteries in physics – including why there is much more matter than antimatter in the universe. While antielectrons (positrons) can be created in a small lab, antiprotons can only be created at large and expensive accelerators. This limits where antimatter experiments can be done. But now, physicists on the BASE collaboration at CERN have shown that it should be possible to transport antiprotons by road. Protons stood in for antiprotons in their demonstration and the particles were held in an electromagnetic trap at cryogenic temperatures and ultralow pressure. By transporting their BASE-STEP system around CERN’s Meyrin site, they showed it was stable and robust enough to handle the rigors of road travel. The system will now be re-configured to transport antiprotons about 700 km to Germany’s Heinrich Heine University. There, physicists hope to search for charge–parity–time (CPT) violations in protons and antiprotons with a precision at least 100 times higher than is currently possible at CERN. The BASE collaboration is also cited in our Top 10 Breakthroughs of 2025 for their quantum control of a single antiproton.

Solid-state nuclear clock ticks ever closer

Solid quartz crystals revolutionized time keeping in the 20th century, so could solid-state nuclear clocks soon do the same? Today, the best timekeepers use the light emitted in atomic transitions. In principle, even better clocks could be made using very-low-energy gamma-rays emitted in some nuclear transitions. Nuclei are much smaller than atoms and these transitions are governed by the strong force. This means that such nuclear clocks would be far less susceptible to performance-degrading electromagnetic noise. And unlike atomic clocks, the nuclei could be embedded in solids – which would greatly simplify clock design. Thorium-229 shows great promise as a clock nucleus but it has two practical shortcomings: it is radioactive and extremely expensive. The solution to both of these problems is a clock design that uses only a tiny amount of thorium-229. Now researchers in the US have shown that physical vapour deposition can used to create extremely thin films of thorium tetrafluoride. Characterization using a vacuum ultraviolet laser confirmed the accessibility of the clock transition – but its lifetime was shorter and the signal less intense than measured in thorium-doped crystals. However, the researchers believe that these unexpected results should not dissuade those aiming to build nuclear clocks.

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Quantum science and technology: highlights of 2025

Margaret Harris — Sun, 28 Dec 2025 14:00:13 +0000

There’s only a few days left in the International Year of Quantum Science and Technology, but we’re still finding plenty to celebrate here at Physics World HQ thanks to a long list of groundbreaking work by quantum physicists in 2025. Here are a few of our favourite stories from the past 12 months.

Observing negative time in atom-photon interactions

By this point in 2025, “negative time” may sound like the answer to the question “How long have I got left to buy holiday presents for my loved ones?” Earlier in the year, though, physicists led by experimentalist Aephraim Steinberg of the University of Toronto, Canada and theorist Howard Wiseman of Griffith University in Australia showed that the concept can also describe the average amount of time a photon spends in an excited atomic state. While experts have cautioned against interpreting “negative time” too literally – we aren’t in time machine territory here – it does seem like there’s something interesting going on in this system of ultracold rubidium atoms.

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Creating an operating system for quantum networks

It is a truth universally acknowledged that any sufficiently advanced technology must be in want of a simple system to operate it. In April, the quantum world passed this milestone thanks to Stephanie Wehner and colleagues at Delft University of Technology in the Netherlands. Their operating system is called QNodeOS, and they developed it with the aim of improving access to quantum computing for the 99.99999% percent of people who aren’t (and mostly don’t need to be) intimately familiar with how quantum information processors work. Another advantage of QNodeOS is that it makes it easier for classical and quantum machines (and quantum devices built with different qbit architectures) to communicate with each other.

Pushing the boundary between the quantum and classical worlds

How big does an object have to be before it stops being quantum and starts behaving like the billiard-ball-like solids familiar from introductory classical mechanics courses? It’s a question that featured in our annual “Breakthrough of the Year” back in 2021, when two independent teams demonstrated quantum entanglement in pairs of 10-micron drumheads, and we’re returning to it this year in a different system: levitated nanoparticles around 100 nm in diameter.

In one boundary-pushing experiment, Massimiliano Rossi and colleagues at ETH Zurich, Switzerland and the Institute of Photonic Sciences in Barcelona, Spain cooled silica nanoparticles enough to extend their wave-like behaviour to 73 pm. In another study, Kiyotaka Aikawa and colleagues at the University of Tokyo, Japan performed the first quantum mechanical squeezing on a nanoparticle, narrowing its velocity distribution at the expense of its momentum distribution. We may not know exactly where the quantum-classical boundary is yet, but the list of quantum behaviours we’ve observed in usually-not-quantum objects keeps getting longer.

Using a quantum computer to generate quantum random numbers

What’s the best way to generate random numbers? In part, the answer depends on how random those numbers really need to be. For many applications, the pseudorandom numbers generated by classical computers, or the random-but-with-systematic-biases numbers found in, say, radio static, are good enough. But if you really, really need those numbers to be random, you need a quantum source – and thanks to work published this year by Scott Aaronson, Shi-Han Hung, Marco Pistoia and colleagues, that quantum source can now be a quantum computer. Which is a neat way of tying things together, don’t you think?

Giving Schrödinger’s cats a nuclear option

Quantum cats Left to right are UNSW researchers Benjamin Wilhelm, Xi Yu, Andrea Morello, Danielle Holmes. (Courtesy: UNSW Sydney)

Finally, we would be remiss not to mention the work of Andrea Morello and colleagues at the University of New South Wales, Australia. This year, they became the first to create quantum superpositions known as a Schrödinger’s cat states in a heavy atom, antimony, that has a large nuclear spin. They also created what is certainly the year’s best scientific team photo, posing with cats on their laps and deadpan expressions more usually associated with too-cool-for-school indie musicians.

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So congratulations to them, and to all the other teams in this list, for setting the bar high in a year that offered plenty for the quantum community to celebrate. We hope you enjoyed the International Year of Quantum Science and Technology, and we look forward to many more exciting discoveries in 2026.

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Medical physics and biotechnology: highlights of 2025

Tami Freeman — Sat, 27 Dec 2025 10:00:29 +0000

This year saw Physics World report on a raft of innovative and exciting developments in the worlds of medical physics and biotech. These included novel cancer therapies using low-temperature plasma or laser ablation, intriguing new devices such as biodegradable bone screws and a pacemaker smaller than a grain of rice, and neural engineering breakthroughs including an ultrathin bioelectric implant that improves movement in rats with spinal cord injuries and a tiny brain sensor that enables thought control of external devices. Here are a few more research highlights that caught my eye.

Vision transformed

One remarkable device introduced in 2025 was an eye implant that restored vision to patients with incurable sight loss. In a clinical study headed up at the University of Bonn, participants with sight loss due to age-related macular degeneration had a tiny wireless implant inserted under their retina. Used in combination with specialized glasses, the system restored the ability to read in 27 of 32 participants followed up a year later.

Learning to read again Study participant Sheila Irvine, a patient at Moorfields Eye Hospital, training with the PRIMA device. (Courtesy: Moorfields Eye Hospital)

We also described a contact lens that enables wearers to see near-infrared light without night vision goggles, reported on an fascinating retinal stimulation technique that enabled volunteers to see colours never before seen by the human eye, and chatted with researchers in Hungary about how a tiny dissolvable eye insert they are developing could help astronauts suffering from eye conditions.

Radiation therapy advances

2025 saw several firsts in the field of radiation therapy. Researchers in Germany performed the first cancer treatment using a radioactive carbon ion beam, on a mouse with a bone tumour close to the spine. And a team at the Trento Proton Therapy Centre in Italy delivered the first clinical treatments using proton arc therapy – a development that made it onto our top 10 Breakthroughs of the Year.

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Meanwhile, the ASTRO meeting saw Leo Cancer Care introduce its first upright photon therapy system, called Grace, which will deliver X-ray radiation to patients in an upright position. This new take on radiation delivery is also under investigation by a team at RaySearch Laboratories, who showed that combining static arcs and shoot-through beams could increase plan quality and reduce delivery times in upright proton therapy.

Among other new developments, there’s a low-cost, dual-robot radiotherapy system built by a team in Canada and targeted for use in low-resource settings, a study from Australia showing that combining microbeam radiation therapy with targeted radiosensitizers can optimize brain cancer treatment, and an investigation at Moffitt Cancer Center examining how skin luminance imaging improves Cherenkov-based radiotherapy dosimetry.

The impact of AI

It’s particularly interesting to examine how the rapid evolution of artificial intelligence (AI) is impacting healthcare, especially considering its potential for use in data-intensive tasks. Earlier this year, a team at Northwestern Medicine integrated a generative AI tool into a live clinical workflow for the first time, using it to draft radiology reports on X-ray images. In routine use, the AI model increased documentation efficiency by an average of 15.5%, while maintaining diagnostic accuracy.

Samir Abboud: “For me and my colleagues, it’s not an exaggeration to say that [the AI tool] doubled our efficiency.” (Courtesy: José M Osorio/Northwestern Medicine)

Other promising applications include identifying hidden heart disease from electrocardiogram traces, contouring targets for brachytherapy treatment planning and detecting abnormalities in blood smear samples.

When introducing AI into the clinic, however, it’s essential that any AI-driven software is accurate, safe and trustworthy. To help assess these factors, a multinational research team identified potential pitfalls in the evaluation of algorithmic bias in AI radiology models, suggesting best practices to mitigate such bias.

A quantum focus

Finally, with 2025 being the International Year of Quantum Science and Technology, Physics World examined how quantum physics looks set to play a key role in medicine and healthcare. Many quantum-based companies and institutions are already working in the healthcare sector, with quantum sensors, in particular, close to being commercialized. As detailed in this feature on quantum sensing, such technologies are being applied for applications ranging from lab and point-of-care diagnostics to consumer wearables for medical monitoring, body scanning and microscopy.

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Alongside, scientists at Jagiellonian University are applying quantum entanglement to cancer diagnostics and developing the world’s first whole-body quantum PET scanner, while researchers at the University of Warwick have created an ultrasensitive magnetometer based on nitrogen-vacancy centres in diamond that could detect small cancer metastases via keyhole surgery. There’s even a team designing a protein qubit that can be produced directly inside living cells and used as a magnetic field sensor (which also featured in this year’s top 10 breakthroughs).

And in September, we ran a Physics World Live event examining how quantum optics, quantum sensors and quantum entanglement can enable advanced disease diagnostics and transform medical imaging. The recording is available to watch here.

The post Medical physics and biotechnology: highlights of 2025 appeared first on Physics World.

+ ‘Kinetic electronics’ make self-connecting circuits + https://physicsworld.com/a/kinetic-electronics-make-self-connecting-circuits/ + Fri, 14 Aug 2026 08:00:02 +0000 + + + + + https://physicsworld.com/?p=129756 + Eventual goal is electronic devices that can reconfigure and even repair themselves

The post ‘Kinetic electronics’ make self-connecting circuits appeared first on Physics World.

Check your physics knowledge with our bumper end-of-year quiz

No Author — Wed, 24 Dec 2025 10:00:26 +0000

How well have you been following events in physics? There are 20 questions in total: blue is your current question and white means unanswered, with green and red being right and wrong.

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16–20 Top quark – congratulations, you’ve hit Einstein level

11–15 Strong force – good but not quite Nobel standard

6–10 Weak force – better interaction needed

0–5 Bottom quark – not even wrong

The post Check your physics knowledge with our bumper end-of-year quiz appeared first on Physics World.

How did you get on?

12 words Warming up nicely

16 words Getting hot, hot, hot

20 words Top dog!

Fancy some more? Check out our puzzles page.

The post Word flower puzzle no. 7 appeared first on Physics World.

ZAP-X radiosurgery and ZAP-Axon SRS planning: technology overview, workflow and complex case insights from a leading SRS centre

No Author — Wed, 24 Dec 2025 09:11:06 +0000

ZAP-X is a next-generation, cobalt-free, vault-free stereotactic radiosurgery system purpose-built for the brain. Delivering highly precise, non-invasive treatments with exceptionally low whole-brain and whole-body dose, ZAP-X’s gyroscopic beam delivery, refined beam geometry and fully integrated workflow enable state-of-the-art SRS without the burdens of radioactive sources or traditional radiation bunkers.

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Theresa Hofman

Theresa Hofman is deputy head of medical physics at the European Radiosurgery Center Munich (ERCM), specializing in stereotactic radiosurgery with the CyberKnife and ZAP‑X systems. She has been part of the ERCM team since 2018 and has extensive clinical experience with ZAP‑X, one of the first centres worldwide to implement the technology in 2021. Since then, the team has treated more than 900 patients with ZAP‑X, and she is deeply involved in both clinical use and evaluation of its planning software.

She holds a master’s degree in physics from Ludwig Maximilian University of Munich, where she authored two first‑author publications on range verification in carbon‑ion therapy. At ERCM, she has published additional first‑author studies on CyberKnife kidney‑treatment accuracy and on comparative planning between ZAP‑X and CyberKnife. She is currently conducting further research on the latest ZAP‑X planning software. Her work is driven by the goal of advancing high‑quality radiosurgery and ensuring the best possible treatment for every patient.

The post ZAP-X radiosurgery and ZAP-Axon SRS planning: technology overview, workflow and complex case insights from a leading SRS centre appeared first on Physics World.

Oscar-winning computer scientist on the physics of computer animation

Margaret Harris — Tue, 23 Dec 2025 14:03:03 +0000

This episode of the Physics World Weekly podcast features Pat Hanrahan, who studied nuclear engineering and biophysics before becoming a founding employee of Pixar Animation Studios. As well as winning three Academy Awards for his work on computer animation, Hanrahan won the Association for Computing Machinery’s A M Turing Award for his contributions to 3D computer graphics, or CGI.

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Earlier this year, Hanrahan spoke to Physics World’s Margaret Harris at the Heidelberg Laureate Forum in Germany. He explains how he was introduced to computer graphics by his need to visualize the results of computer simulations of nervous systems. That initial interest led him to Pixar and his development of physically-based rendering, which uses the principles of physics to create realistic images.

Hanrahan explains that light interacts with different materials in very different ways, making detailed animations very challenging. Indeed, he says that creating realistic looking skin is particularly difficult – comparing it to the quest for a grand unified theory in physics.

He also talks about how having a background in physics has helped his career – citing his physicist’s knack for creating good models and then using them to solve problems.

The post Oscar-winning computer scientist on the physics of computer animation appeared first on Physics World.

Physics-based battery model parameterization from impedance data

No Author — Tue, 23 Dec 2025 07:18:44 +0000

Electrochemical impedance spectroscopy (EIS) provides valuable insights into the physical processes within batteries – but how can these measurements directly inform physics-based models? In this webinar, we present recent work showing how impedance data can be used to extract grouped parameters for physics-based models such as the Doyle–Fuller–Newman (DFN) model or the reduced-order single-particle model with electrolyte (SPMe).

We will introduce PyBaMM (Python Battery Mathematical Modelling), an open-source framework for flexible and efficient battery simulation, and show how our extension, PyBaMM-EIS, enables fast numerical impedance computation for any implemented model at any operating point. We also demonstrate how PyBOP, another open-source tool, performs automated parameter fitting of models using measured impedance data across multiple states of charge.

Battery modelling is challenging, and obtaining accurate fits can be difficult. Our technique offers a flexible way to update model equations and parameterize models using impedance data.

Join us to see how our tools create a smooth path from measurement to model to simulation.

An interactive Q&A session follows the presentation.

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Noël Hallemans

Noël Hallemans is a postdoctoral research assistant in engineering science at the University of Oxford, where he previously lectured in mathematics at St Hugh’s College. He earned his PhD in 2023 from the Vrije Universiteit Brussel and the University of Warwick, focusing on frequency-domain, data-driven modelling of electrochemical systems.

His research at the Battery Intelligence Lab, led by Professor David Howey, integrates electrochemical impedance spectroscopy (EIS) with physics-based modelling to improve understanding and prediction of battery behaviour. He also develops multisine EIS techniques for battery characterisation during operation (for example, charging or relaxation).

The post Physics-based battery model parameterization from impedance data appeared first on Physics World.

+ Researchers propose ‘economic Q’ metric for judging fusion power plant viability + https://physicsworld.com/a/researchers-propose-economic-q-metric-for-judging-fusion-power-plant-viability/ + Thu, 13 Aug 2026 11:59:03 +0000 + + + + https://physicsworld.com/?p=129749 + New framework includes 10 parameters that can be used to evaluate the viability of fusion

The post Researchers propose ‘economic Q’ metric for judging fusion power plant viability appeared first on Physics World.

Higgs decay to muon–antimuon pairs sheds light on the origin of mass

No Author — Mon, 22 Dec 2025 15:51:44 +0000

The quantum tunnelling of hydrogen atoms plays a central role in many physical, chemical and biological process, but a practical means of controlling it has proved elusive. Researchers from the University of Tokyo, Japan have now demonstrated that the way hydrogen permeates through a material depends on the degree of symmetry in the material’s crystal structure. By controlling this symmetry, scientists could therefore gain control over hydrogen’s ability to tunnel, potentially leading to safer and more efficient media for storing this industrially important clean-burning fuel.

“We found that hydrogen undergoes pronounced quantum tunnelling in a highly symmetric crystal environment, whereas the tunnelling is strongly suppressed when the symmetry is lowered,” explains Katsuyuki Fukutani, who led the research together with colleagues Takahiro Ozawa and Sudhansu Sekhar Das. “This is particularly exciting because it identifies crystal symmetry as a fundamental principle for controlling the quantum behaviour of hydrogen in materials, opening new possibilities for tailoring hydrogen transport.”

A model hydrogen-storage material

The researchers, who work at Tokyo’s Institute of Industrial Science, obtained their results by studying how hydrogen atoms move through a model hydrogen-storage material, vanadium, at low temperatures. To do this, they combined two complementary techniques. The first is called nuclear reaction analysis and it measures the hydrogen’s depth distribution directly with high resolution. The second involves measuring electrical resistance, which sensitively monitors how the hydrogen redistributes itself over time.

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These measurements revealed that at temperatures of around 70 K, hydrogen atoms begin to migrate through vanadium’s crystal lattice, hopping between its interstitial spaces. At low hydrogen concentrations, this hopping occurs within a highly symmetric structure known as α-phase vanadium, and the hydrogen atoms easily tunnel between neighbouring lattice sites. At higher hydrogen concentrations, however, vanadium’s crystal lattice distorts, forming a β-phase. Under these conditions, the hydrogen atoms must overcome an energy barrier (of 148 meV in this case) before they can tunnel to neighbouring sites.

Quantum tunnelling or classical thermal activation?

Based on changes to vanadium’s electrical resistance, the researchers were able to calculate the diffusion coefficient of hydrogen over a wide range of temperatures, including those for which quantum tunnelling is important. They then interpreted these results using quantum-mechanical calculations of hydrogen motion, which revealed that the crystal symmetry determines whether hydrogen moves by quantum tunnelling or by classical thermal activation. They found that in the α-phase, hydrogen’s ground states are delocalized over tetrahedral sites thanks to tunnelling. In the β-phase, in contrast, the uniaxial strain produced by the distortion of the crystal lattice leads the quantum states of the hydrogen atoms to localize around certain (O_z) sites in the material.

Hydrogen is the lightest element, so Fukutani says it’s not surprising that it exhibits pronounced quantum behaviour. However, while quantum tunnelling had long been assumed to play an important role in hydrogen diffusion, it was difficult to obtain direct experimental evidence for it because we cannot easily observe hydrogen inside materials using conventional techniques. “We wanted to clarify how hydrogen actually behaves in the quantum regime and identify the factors that control its tunnelling,” he explains.

New possibilities for controlling hydrogen permeation and storage

“Our findings suggest that hydrogen transport can be controlled by tuning quantum tunnelling through crystal symmetry — for example by applying external strain,” he adds. “This capability opens up new possibilities for controlling hydrogen permeation, storage and even catalytic reactions.”

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More broadly, Fukutani says the team’s work establishes crystal symmetry as a new design principle for tailoring quantum hydrogen behaviour in functional materials. The Tokyo researchers now plan to extend their work to a wider range of hydrogen storage media, including metal alloys and oxide materials. “Ultimately, we hope to establish a universal framework describing how local atomic structure and crystal symmetry govern the quantum behaviour of hydrogen,” Fukutani tells Physics World.

They report their present work in Nature Communications.

The post Crystal symmetry controls hydrogen’s quantum tunnelling appeared first on Physics World.

Russia plans to revive abandoned Soviet-era particle accelerator

No Author — Mon, 22 Dec 2025 10:00:01 +0000

(Courtesy: Shutterstock/svekloid)

All scientific inquiry involves some kind of uncertainty, but the uncertainties in cosmology are particularly daunting. As well as being complex and difficult to describe, the systems cosmologists investigate are almost by definition out of reach. In these conditions of uncertainty, how confident can we be in the models we’ve built? How can we come to know how galaxies form, how the universe began or how much dark matter it contains?

In The Random Universe: How Models and Probability Help us Make Sense of the Cosmos, cosmologist and astrophysicist Andrew Jaffe offers a masterful and refreshing take on these questions. As the director of the Centre for Inference and Cosmology at Imperial College London, UK, and a past co-investigator on ESA’s Planck satellite that provided us with so much new information about the cosmos, Jaffe is well-equipped to walk readers through the tools that allow us to learn about the world despite its uncertainties. Anchoring his insights in beautifully narrated episodes from the history of physics, astrophysics and cosmology, he sheds light on how our theories of the universe evolved into our current best cosmological model – which nonetheless still has limitations.

Jaffe is particularly good at recounting how we refined, revised and even replaced some of our assumptions in light of incoming evidence such as the first measurements of stellar distance; the discovery of galaxies beyond our own; and precise measurements of cosmological parameters. Throughout this journey, he engages thoughtfully with a rich philosophical tradition that runs from David Hume in the 18th century through Willard Van Orman Quine, Imre Lakatos and Paul Feyerabend in the 20th.

Bayes’ theorem is important because it tells us how to update our degree of belief in light of new evidence
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The book’s main protagonist, though, is the mathematician Thomas Bayes. For Jaffe, Bayesian probability is key to dealing with uncertainty, and even to solving Hume’s notorious problem of induction: how do we justify inferences from a finite set of observations to generalizations that go beyond them? Bayes’ theorem is important, Jaffe argues, because it tells us how to update our degree of belief in light of new evidence. It shows us why and how, even in an uncertain world, “the more observations we make, the surer we become”.

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Of course, before we can use probability to deal with uncertainty, we first need a model. As Jaffe puts it, “Absent a model, I can’t assign a probability, and absent a probability, I can’t quantify my uncertainty about the world.” So, what exactly is a model? I found Jaffe’s answer to be one of the most captivating elements of the book. As the title of a subsection of chapter five puts it, “a model is a story about the world”. Without models, Jaffe tells us, our world would be an unexplained series of unrelated events. Models are also what allow us to take a finite set of data and use it to create something new. Without this leap, Jaffe suggests, we cannot learn anything about the world, because “you can’t make sense of an experimental result unless you have some model to interpret it”.

Of course, if the way we interpret data depends on our model, then different people may well obtain different interpretations depending on which model and which prior probability they choose. This charge of subjectivity is a longstanding accusation against Bayesians, but Jaffe offers at least a partial solution: “If you and I agree on the model, we should assign the same probability.” This, Jaffe argues, is where objectivity emerges, writing that “we come to the same conclusions if we start from the same premises”.

Models allow us to understand the world by bridging subjectivity with objectivity, and the personal with the collective
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Many contemporary philosophers are at odds with the idealized view of science as an objective and linear enterprise that produces theories from a God’s-eye view. Instead, they strive to portray it as something that is social and human, but reliable nonetheless. Jaffe’s own views seem to align with this endeavour; as he puts it, “the scientific coupling of models and observations is a living, breathing, subjective endeavour, simultaneously collective and personal”. Through their interplay with data, he argues, models allow us to understand the world by bridging subjectivity with objectivity, and the personal with the collective.

Not everyone will agree with Jaffe that Bayesian probability offers a solution to Hume’s problem of induction. Personally, I (or perhaps the hardcore rationalist in me) was not convinced. Nevertheless, I found the book’s thesis – that uncertainty is not a hindrance to knowledge, but an opportunity to learn (and learn more) about the world – simultaneously liberating, humbling and empowering. I recommend The Random Universe to scientists, philosophers and anyone interested in better understanding the role of probability in science; the philosophical problems with how we handle uncertainty; and how our standard cosmological model came to be. I also hope it will encourage more collaborations between philosophers and scientists. There are many questions we can explore further if we work together.

2025 Yale University Press, £25hb, 288pp

The post Knowing through uncertainty: probability and the evolution of our cosmos appeared first on Physics World.

Real-world quantum entanglement is far from an unlimited resource

Daniele Iannotti — Fri, 19 Dec 2025 12:00:34 +0000

Achieving a profound understanding of any subject is hard. When that subject is quantum mechanics, it’s even harder. And when one departs from ideal theoretical scenarios and enters the real world of experimental limitations, it becomes more challenging still – yet that is what physicists at the Freie Universität Berlin (FU-Berlin), Germany recently did by exploring what happens to entanglement theory in real quantum computers. In doing so, they created a bridge between two fields that have so far largely developed in parallel: entanglement theory (rooted in physics) and computational complexity (rooted in computer science).

Ebits, the standard currency of entanglement

In quantum mechanics, a composite system is said to be entangled when its total wavefunction cannot be written as a product of the states of its individual subsystems. This leads to correlations between subsystems that arise from the structure of the quantum state, not from any shared classical information. Many speed-ups achieved in quantum computing, quantum cryptography and quantum metrology rely heavily on entanglement, but not every form of entanglement is equally useful. Only specific kinds of entanglement will enable a given computational or communication task.

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To make quantum technologies practical, the available entangled resources must therefore often be converted into forms suitable for specific applications. One major conversion process involves transforming partially entangled states into, or extracting them from, the maximally entangled bit (ebit) that acts as the standard unit of entanglement. High-fidelity ebits – entangled pairs that are extremely close to the ideal perfectly entangled state – can be distilled from noisy or imperfect entangled states through entanglement distillation, while entanglement dilution allows one to reconstruct the desired entangled states from purified ebits.

In an idealized setting, with an infinite number of copies of entangled states and unlimited computational power, a single quantity called the von Neumann entropy fully determines how many ebits can be extracted or are required. But reality is far less forgiving: we never have infinite resources, and computational power is always limited, just like we don’t have an infinite amount of gold on Earth.

Entanglement under finite resources

In the present work, which is published in Nature Physics, the FU-Berlin team of Lorenzo Leone, Jacopo Rizzo, Jens Eisert and Sofiene Jerbi asked what happens when these ideal assumptions break down. They study the case where only a finite number of entangled states, which can scale at most polynomially with the number of quantum bits (qubits) in the system, are considered and all local operations and classical communication (LOCC) are performed in a finite polynomial time.

They found that the simple correspondence between von Neumann entropy and extractable or required ebits no longer holds: even when a state has a large von Neumann entropy, the number of ebits that can be efficiently extracted may be much lower. In these cases, the number is bounded instead by the min-entropy of the reduced state (an operational measure determined solely by the state’s largest eigenvalue that captures how much entanglement can be reliably distilled from a single copy of the state) without averaging over many uses. On the other hand, even a state with negligible von Neumann entanglement may require a maximal ebit budget for efficient dilution.

Leone and Eisert say they were inspired to perform this study by recent work on so-called pseudo-entangled states, which are states that look at lot more entangled than they are for computationally bounded observers. Their construction of pseudo-entangled states highlights a dramatic worst-case scenario: a state that appears almost unentangled by conventional measures may still require a large number of ebits to create it efficiently. The takeaway is that computability matters, and quantum resources you might have thought were available may be, in effect, locked away simply because they cannot be processed efficiently. In other words, practical limitations make the line between a “resource” and a “usable resource” even sharper.

Quantum resources in a limited world

The researchers say that their study raises multiple questions for future exploration. One such question concerns whether a similar computational‐efficiency gap exists for other quantum resources such as magic and coherence. Another is whether one can build a full resource theory with complexity constraints, where quantities reflect not just what can be converted, but how efficient that conversion is.

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Regardless of the answers, the era of entanglement under infinite book‐keeping is giving way to an era of entanglement under limited books, limited clocks and limited gates. And in this more realistic space, quantum technologies may still shine, but the calculus of what can be done and what can be harnessed needs a serious retooling.

The post Real-world quantum entanglement is far from an unlimited resource appeared first on Physics World.

Hybrid deep-learning model eases brachytherapy planning

Tami Freeman — Fri, 19 Dec 2025 09:30:42 +0000

CTV segmentation test Target contouring in two example slices of a patient’s CT scan, using BCTVNet and 12 comparison models. Red and green contours represent the ground truth and the model predictions, respectively. Each image is annotated with the corresponding Dice similarity coefficient. (Courtesy: CC BY 4.0/Mach. Learn.: Sci. Technol. 10.1088/2632-2153/ae2233

Brachytherapy – a cancer treatment that destroys tumours using small radioactive sources implanted inside the body – plays a critical role in treating cervical cancer, offering an important option for patients with inoperable locally advanced disease. Brachytherapy can deliver high radiation doses directly to the tumour while ensuring nearby healthy tissues receive minimal dose; but its effectiveness relies on accurate delineation of the treatment target. A research team in China is using a hybrid deep-learning model to help with this task.

Planning brachytherapy treatments requires accurate contouring of the clinical target volume (CTV) on a CT scan, a task that’s traditionally performed manually. The limited soft-tissue contrast of CT, however, can result in unclear target boundaries, while applicator or needle insertion (used to deliver the radioactive sources) can deform and displace nearby organs. This makes manual contouring a time-consuming and subjective task that requires a high level of operator expertise.

Automating this process could reduce reliance on operator experience, increase workflow efficiency and improve contouring consistency. With this aim, the research team – headed up by He Ma from Northeastern University and Lin Zhang from Shanghai University of International Business and Economics – developed a 3D hybrid neural network called BCTVNet.

Currently, most brachytherapy segmentation models are based on convolutional neural networks (CNNs). CNNs effectively capture local structural features and can model fine anatomical details but struggle with long-range dependencies, which can cause problems if the target extends across multiple CT slices. Another option is to use transformer-based models that can integrate spatial information across distant regions and slices; but these are less effective at capturing fine-grained local detail.

To combine the strengths of both, BCTVNet integrates CNN with transformer branches to provide strong local detail extraction along with global information integration. BCTVNet performs 3D segmentation directly on post-insertion CT images, enabling the CTV to be defined based on the actual treatment geometry.

Model comparisons

Zhang, Ma and colleagues assessed the performance of BCTVNet using a private CT dataset from 95 patients diagnosed with locally advanced cervical cancer and treated with CT-guided 3D brachytherapy (76 in the training set, 19 in the test set). The scans had an average of 96 slices per patient and a slice thickness of 3 mm.

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CT scans used to plan cervical cancer brachytherapy often exhibit unclear target boundaries. To enhance the local soft-tissue contrast and improve boundary recognition, the researchers pre-processed the CT volumes with a 3D version of the CLAHE (contrast-limited adaptive histogram equalization) algorithm, which processes the entire CT scan as a volumetric input. They then normalized the intensity values to standardize the input for the segmentation models.

The researchers compared BCTVNet with 12 popular CNN- and transformer-based segmentation models, evaluating segmentation performance via a series of metrics, including Dice similarity coefficient (DSC), Jaccard index, Hausdorff distance 95th percentile (HD95) and average surface distance.

Contours generated by BCTVNet were closest to the ground truth, reaching a DSC of 83.24% and a HD95 (maximum distance from ground truth excluding the worst 5%) of 3.53 mm. BCTVNet consistently outperformed the other models across all evaluation metrics. It also demonstrated strong classification accuracy, with a precision of 82.10% and a recall of 85.84%, implying fewer false detections and successful capture of target regions.

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To evaluate the model’s generalizability, the team conducted additional experiments on the public dataset SegTHOR, which contains 60 thoracic 3D CT scans (40 for training, 20 for testing) from patients with oesophageal cancer. Here again, BCTVNet achieved the best scores among all the segmentation models, with the highest average DSC of 87.09% and the lowest average HD95 of 7.39 mm.

“BCTVNet effectively overcomes key challenges in CTV segmentation and achieves superior performance compared to existing methods,” the team concludes. “The proposed approach provides an effective and reliable solution for automatic CTV delineation and can serve as a supportive tool in clinical workflows.”

The researchers report their findings in Machine Learning: Science and Technology.

The post Hybrid deep-learning model eases brachytherapy planning appeared first on Physics World.

+ Physicists extend Hawking’s black hole laws to dynamical objects + https://physicsworld.com/a/physicists-extend-hawkings-black-hole-laws-to-dynamical-objects/ + Wed, 12 Aug 2026 11:00:18 +0000 + + + + https://physicsworld.com/?p=129731 + Thermodynamics can describe the mechanics of black holes that change over time

The post Physicists extend Hawking’s black hole laws to dynamical objects appeared first on Physics World.

Pioneers of 2D metals win the Physics World 2025 Breakthrough of the Year

Hamish Johnston — Thu, 18 Dec 2025 14:15:42 +0000

Under pressure A researcher in Beijing operates an apparatus used to make 2D metals. (Courtesy: CAS IOP/Handout via Xinhua)

The Physics World 2025 Breakthrough of the Year is awarded to Guangyu Zhang, Luojun Du and colleagues at the Institute of Physics of the Chinese Academy of Sciences for producing the first 2D sheets of metal. The team produced five atomically thin 2D metals – bismuth, tin, lead, indium and gallium – with the thinnest being around 6.3 Å. The researchers say their work is just the “tip of the iceberg” and now aim to use their new materials to probe the fundamentals of physics. Their breakthrough could also lead to the development of new technologies.

Since the discovery of graphene – a sheet of carbon just one atom thick – in 2004, hundreds of other 2D materials have been fabricated and studied. In most of these, layers of covalently bonded atoms are separated by gaps where neighbouring layers are held together only by weak van der Waals (vdW) interactions, making it relatively easy to “shave off” single layers to make 2D sheets. Many thought that making atomically thin metals would be impossible given that each atom in a metal is strongly bonded to surrounding atoms in all directions.

The technique developed by Zhang, Du and colleagues involves heating powders of pure metals between two monolayer-MoS2/sapphire vdW anvils. Once the metal powders are melted into a droplet, the researchers applied a pressure of 200 MPa and continued this “vdW squeezing” until the opposite sides of the anvils cooled to room temperature and 2D sheets of metal were formed.

“Right now, we have reported five single element metals, but actually we can do more because of the 88 metals in the periodic table,” Zhang explains in today’s episode of the Physics World Weekly podcast. In the podcast, he also talks about the team’s motivation creating 2D metals and some of the possible technological applications of the materials.

The Breakthrough of the Year was chosen by the Physics World editorial team. We looked back at all the scientific discoveries we have reported on since 1 January and picked the most important. In addition to being reported in Physics World in 2025, the breakthrough must meet the following criteria:

Significant advance in knowledge or understanding

Importance of work for scientific progress and/or development of real-world applications

Of general interest to Physics World readers

Before we picked our winners, we released the Physics World Top 10 Breakthroughs for 2025, which served as our shortlist. The other nine breakthroughs are listed below in no particular order.

Finding the stuff of life on an asteroid

Analysing returned samples Tim McCoy (right), curator of meteorites at the Smithsonian’s National Museum of Natural History, and research geologist Cari Corrigan examine scanning electron microscope (SEM) images of a Bennu sample. (Courtesy: James Di Loreto, Smithsonian)

To Tim McCoy, Sara Russell, Danny Glavin, Jason Dworkin, Yoshihiro Furukawa, Ann Nguyen, Scott Sandford, Zack Gainsforth and an international team of collaborators for identifying salt, ammonia, sugar, nitrogen- and oxygen-rich organic materials, and traces of metal-rich supernova dust, in samples returned from the near-Earth asteroid 101955 Bennu. The incredible chemical richness of this asteroid, which NASA’s OSIRIS-REx spacecraft visited in 2020, lends support to the longstanding hypothesis that asteroid impacts could have “seeded” the early Earth with the raw ingredients needed for life to form. The discoveries also enhance our understanding of how Bennu and other objects in the solar system formed out of the disc of material that coalesced around the young Sun.

The first superfluid molecule

To Takamasa Momose of the University of British Columbia, Canada, and Susumu Kuma of the RIKEN Atomic, Molecular and Optical Physics Laboratory, Japan for observing superfluidity in a molecule for the first time. Molecular hydrogen is the simplest and lightest of all molecules, and theorists predicted that it would enter a superfluid state at a temperature between 1‒2 K. But this is well below the molecule’s freezing point of 13.8 K, so Momose, Kuma and colleagues first had to develop a way to keep the hydrogen in a liquid state. Once they did that, they then had to work out how to detect the onset of superfluidity. It took them nearly 20 years, but by confining clusters of hydrogen molecules inside helium nanodroplets, embedding a methane molecule within the clusters, and monitoring the methane’s rotation, they were finally able to do it. They now plan to study larger clusters of hydrogen, with the aim of exploring the boundary between classical and quantum behaviour in this system.

Hollow-core fibres break 40-year limit on light transmission

To researchers at the University of Southampton and Microsoft Azure Fiber in the UK, for developing a new type of optical fibre that reduces signal loss, boosts bandwidth and promises faster, greener communications. The team, led by Francesco Poletti, achieved this feat by replacing the glass core of a conventional fibre with air and using glass membranes that reflect light at certain frequencies back into the core to trap the light and keep it moving through the fibre’s hollow centre. Their results show that the hollow-core fibres exhibit 35% less attenuation than standard glass fibres – implying that fewer amplifiers would be needed in long cables – and increase transmission speeds by 45%. Microsoft has begun testing the new fibres in real systems, installing segments in its network and sending live traffic through them. These trials open the door to gradual rollout and Poletti suggests that the hollow-core fibres could one day replace existing undersea cables.

First patient treatments delivered with proton arc therapy

PAT pioneers The research team in the proton therapy gantry room. (Courtesy: UO Fisica Sanitaria and UO Protonterapia, APSS, Trento)

To Francesco Fracchiolla and colleagues at the Trento Proton Therapy Centre in Italy for delivering the first clinical treatments using proton arc therapy (PAT). Proton therapy – a precision cancer treatment – is usually performed using pencil-beam scanning to precisely paint the dose onto the tumour. But this approach can be limited by the small number of beam directions deliverable in an acceptable treatment time. PAT overcomes this by moving to an arc trajectory with protons delivered over a large number of beam angles and the potential to optimize the number of energies used for each beam direction. Working with researchers at RaySearch Laboratories in Sweden, the team performed successful dosimetric comparisons with clinical proton therapy plans. Following a feasibility test that confirmed the viability of clinical PAT delivery, the researchers used PAT to treat nine cancer patients. Importantly, all treatments were performed using the centre’s existing proton therapy system and clinical workflow.

A protein qubit for quantum biosensing

To Peter Maurer and David Awschalom at the University of Chicago Pritzker School of Molecular Engineering and colleagues for designing a protein quantum bit (qubit) that can be produced directly inside living cells and used as a magnetic field sensor. While many of today’s quantum sensors are based on nitrogen–vacancy (NV) centres in diamond, they are large and hard to position inside living cells. Instead, the team used fluorescent proteins, which are just 3 nm in diameter and can be produced by cells at a desired location with atomic precision. These proteins possess similar optical and spin properties to those of NV centre-based qubits – namely that they have a metastable triplet state. The researchers used a near-infrared laser pulse to optically address a yellow fluorescent protein and read out its triplet spin state with up to 20% spin contrast. They then genetically modified the protein to be expressed in bacterial cells and measured signals with a contrast of up to 8%. They note that although this performance does not match that of NV quantum sensors, it could enable magnetic resonance measurements directly inside living cells, which NV centres cannot do.

Highest-resolution images ever taken of a single atom

To the team led by Yichao Zhang at the University of Maryland and Pinshane Huang of the University of Illinois at Urbana-Champaign for capturing the highest-resolution images ever taken of individual atoms in a material. The team used an electron-microscopy technique called electron ptychography to achieve a resolution of 15 pm, which is about 10 times smaller than the size of an atom. They studied a stack of two atomically-thin layers of tungsten diselenide, which were rotated relative to each other to create a moiré superlattice. These twisted 2D materials are of great interest to physicists because their electronic properties can change dramatically with small changes in rotation angle. The extraordinary resolution of their microscope allowed them to visualize collective vibrations in the material called moiré phasons. These are similar to phonons, but had never been observed directly until now. The team’s observations align with theoretical predictions for moiré phasons. Their microscopy technique should boost our understanding of the role that moiré phasons and other lattice vibrations play in the physics of solids. This could lead to the engineering of new and useful materials.

Quantum control of individual antiprotons

Exquisite control Physicist Barbara Latacz at the BASE experiment at CERN. (Courtesy: CERN)

To CERN’s BASE collaboration for being the first to perform coherent spin spectroscopy on a single antiproton – the antimatter counterpart of the proton. Their breakthrough is the most precise measurement yet of the antiproton’s magnetic properties, and could be used to test the Standard Model of particle physics. The experiment begins with the creation of high-energy antiprotons in an accelerator. These must be cooled (slowed down) to cryogenic temperatures without being lost to annihilation. Then, a single antiproton is held in an ultracold electromagnetic trap, where microwave pulses manipulate its spin state. The resulting resonance peak was 16 times narrower than previous measurements, enabling a significant leap in precision. This level of quantum control opens the door to highly sensitive comparisons of the properties of matter (protons) and antimatter (antiprotons). Unexpected differences could point to new physics beyond the Standard Model and may also reveal why there is much more matter than antimatter in the visible universe.

A smartphone-based early warning system for earthquakes

To Richard Allen, director of the Berkeley Seismological Laboratory at the University of California, Berkeley, and Google’s Marc Stogaitis and colleagues for creating a global network of Android smartphones that acts as an earthquake early warning system. Traditional early warning systems use networks of seismic sensors that rapidly detect earthquakes in areas close to the epicentre and issue warnings across the affected region. Building such seismic networks, however, is expensive, and many earthquake-prone regions do not have them. The researchers utilized the accelerometer in millions of phones in 98 countries to create the Android Earthquake Alert (AEA) system. Testing the app between 2021 and 2024 led to the detection of an average of 312 earthquakes a month, with magnitudes ranging from 1.9 to 7.8. For earthquakes of magnitude 4.5 or higher, the system sent “TakeAction” alerts to users, sending them, on average, 60 times per month for an average of 18 million individual alerts per month. The system also delivered lesser “BeAware” alerts to regions expected to experience a shaking intensity of magnitude 3 or 4. The team now aims to produce maps of ground shaking, which could assist the emergency response services following an earthquake.

A “weather map” for a gas giant exoplanet

To Lisa Nortmann at Germany’s University of Göttingen and colleagues for creating the first detailed “weather map” of an exoplanet. The forecast for exoplanet WASP-127b is brutal with winds reaching 33,000 km/hr, which is much faster than winds found anywhere in the Solar System. The WASP-127b is a gas giant located about 520 light–years from Earth and the team used the CRIRES+ instrument on the European Southern Observatory’s Very Large Telescope to observe the exoplanet as it transited across its star in less than 7 h. Spectral analysis of the starlight that filtered through WASP-127b’s atmosphere revealed Doppler shifts caused by supersonic equatorial winds. By analysing the range of Doppler shifts, the team created a rough weather map of WASP-127b, even though they could not resolve light coming from specific locations on the exoplanet. Nortmann and colleagues concluded that the exoplanet’s poles are cooler that the rest of WASP-127b, where temperatures can exceed 1000 °C. Water vapour was detected in the atmosphere, raising the possibility of exotic forms of rain.

Physics World‘s coverage of the Breakthrough of the Year is supported by Reports on Progress in Physics, which offers unparalleled visibility for your ground-breaking research.

+ Memory effects in nanoparticle suspensions + https://physicsworld.com/a/memory-effects-in-nanoparticle-suspensions/ + Wed, 12 Aug 2026 08:40:00 +0000 + + + https://physicsworld.com/?p=129305 + Researchers uncover how memory effects arise in electrically aligned nanoparticles in suspension and use this understanding to accelerate relaxation

The post Memory effects in nanoparticle suspensions appeared first on Physics World.

How to make 2D metals: Guangyu Zhang on his team’s award-winning research

Hamish Johnston — Thu, 18 Dec 2025 14:13:52 +0000

This episode of the Physics World Weekly podcast features Guangyu Zhang. Along with his colleagues at the Institute of Physics of the Chinese Academy of Sciences, Zhang has bagged the 2025 Physics World Breakthrough of the Year award for creating the first 2D metals.

In a wide-ranging conversation, we chat about the motivation behind the team’s research; the challenges in making 2D metals and how these were overcome; and how 2D metals could be used to boost our understanding of condensed-matter physics and create new technologies.

I am also joined by my Physics World colleague Matin Durrani to talk about some of the exciting physics that we will be showcasing in 2025.

Physics World‘s coverage of the Breakthrough of the Year is supported by Reports on Progress in Physics, which offers unparalleled visibility for your ground-breaking research.

+ When topology meets entanglement + https://physicsworld.com/a/when-topology-meets-entanglement/ + Wed, 12 Aug 2026 08:38:10 +0000 + + + https://physicsworld.com/?p=129718 + New research explores how a material’s unusual topological behaviour is connected to the way quantum states are shared between different parts of its lattice

The post When topology meets entanglement appeared first on Physics World.

Quantum cluster targets business growth

No Author — Thu, 18 Dec 2025 12:52:22 +0000

Julia Sutcliffe (second from the left), Chief Scientific Advisor for the UK’s Department for Business and Trade, visits the NQCC’s experimental facilities on the Harwell Cluster (Courtesy: NQCC)

Ever since the National Quantum Computing Centre was launched five years ago, its core mission has been to accelerate the pathway towards practical adoption of the technology. That has required technical innovation to scale up hardware platforms and create the software tools and algorithms needed to tackle real-world applications, but there has also been a strong focus on engaging with companies to build connections, provide access to quantum resources, and identify opportunities for deriving near-term value from quantum computing.

It makes sense, then, that the NQCC should form the cornerstone of a new Quantum Cluster at the Harwell Campus of Science and Innovation in Oxfordshire. The hope is that the NQCC’s technical expertise and infrastructure, combined with the services and facilities available on the wider Harwell Campus, will provide a magnet for new quantum start-ups as well as overseas companies that are seeking to establish a presence within the UK’s quantum ecosystem.

By accelerating collaboration across government, industry and academia, we will turn research excellence into industrial strength.

“We want to leverage the public investment that has been made into the NQCC to catalyse business growth and attract more investment into the UK’s quantum sector,” said Najwa Sidqi, manager of the Harwell Quantum Cluster, at the official launch event in November. “By accelerating collaboration across government, industry and academia, we will turn research excellence into industrial strength.”

The cluster, which has been ramping up its activities over the last year, is working to ambitious targets. Over the next decade the aim is to incubate at least 100 quantum companies on the Harwell site, create more than 1000 skilled jobs, and generate more than £1 billion of private and public investment. “Our aim is to build the foundations of a globally competitive quantum economy that delivers impact far beyond science and research,” added Sidqi.

Tangible evidence that the approach works is offered by the previous clustering activities on the Harwell Campus, notably the Space Cluster that has expanded rapidly since its launch in 2010. Anchored by the RAL Space national laboratory and bolstered by the presence of ESA and the UK Space Agency, the Space Cluster now comprises more than 100 organizations that range from small start-ups to the UK technology hubs of global heavyweights such as Airbus and Lockheed Martin.

More generally, the survival rate of start-up companies operating on the Harwell site is around 95%, compared with an average of around 50%. “At Harwell there is a high density of innovators sharing the same space, which generates more connections and more ideas,” said Julia Sutcliffe, Chief Scientific Advisor for the UK’s Department for Business and Trade. “It provides an incredible combination of world-class infrastructure and expertise, accelerating the innovation pathway and helping to create a low-risk environment for early-stage businesses and investors.”

The NQCC has already seeded that innovation activity through its early engagement with both quantum companies and end users of the technology. One major initiative has been the testbed programme, which has enabled the NQCC to invest £30m in seven hardware companies to deploy prototype quantum computers on the Harwell Campus. As well as providing access to operational systems based on all of the leading qubit modalities, the testbed programme has also provided an impetus for inward investment and job creation.

One clear example is provided by QuEra Computing, a US-based spin-off from Harvard University and the Massachusetts Institute of Technology that is developing a hardware platform based on neutral atoms. QuEra was one of the companies to win funding through the testbed programme, with the firm setting up a UK-based team to deploy its prototype system on the Harwell Campus. But the company could soon see the benefits of establishing a UK centre for technology development on the site. “Harwell is immensely helpful to us,” said Ed Durking, Corporate Director of QuEra Computing UK. “It’s a nucleus where we enjoy access to world-class talent, vendors, customers, and suppliers.”

On a practical level, establishing its UK headquarters on the Harwell Campus has provided QueEra with easy access to specialist contractors and services for fitting out and its laboratories. In June the company moved into a building that is fully equipped with flexible lab space for R&D and manufacturing, and since then the UK-based team has started to build the company’s most powerful quantum computer at the facility. Longer term, establishing a base within the UK could open the door to new collaborations and funding opportunities for QuEra to further develop its technology, with the company now focused on integrating full error correction into its neutral-atom platform by 2026.

Access to the world-class infrastructure on the Harwell Campus has benefitted the other testbed providers in different ways. For ORCA Computing, a UK company developing and manufacturing photonic quantum computers, the goal was to install a testbed system within Harwell’s high-performance computing centre rather than the NQCC’s experimental labs. “Our focus is to build commercial photonic quantum systems that can be integrated into conventional datacentres, enabling hybrid quantum-classical workflows for real-world applications,” explained Geoff Barnes, Head of Customer Success at ORCA. “Having the NQCC as an expert customer enabled us to demonstrate and validate our capabilities, building the system in our own facility and then deploying it within an operational environment.”

This process provided a valuable learning experience for the ORCA engineers. The experts at Harwell helped them to navigate the constraints of installing equipment within a live datacentre, while also providing practical assistance with the networking infrastructure. Now that the system is up and running, the Harwell site also provides ORCA with an open environment for showcasing its technology to prospective customers. “As well as delivering a testbed system to the NQCC, we can now demonstrate our platform to clients within a real-world setting,” added Barnes. “It has also been a critical step toward commercial deployment on our roadmap, enabling our partners to access our systems remotely for applications development.”

Michael Cuthbert (left), Director of the NQCC, takes Sutcliffe and other visitors on a tour of the national lab (Courtesy: NQCC)

While the NQCC has already played a vital role in supporting companies as they make the transition towards commercialization, the Quantum Cluster has a wider remit to extend those efforts into other quantum technologies, such as sensing and communications, that are already finding real-world applications. It will also have a more specific focus on attracting new investment into the UK, and supporting the growth of companies that are transitioning from the start-up phase to establish larger scale commercial operations.

“In the UK we have traditionally been successful in creating spin-off activities from our strong research base, but it has been more challenging to generate the large capital investments needed to scale businesses in the technology sector,” commented Sidqi. “We want to strengthen that pipeline to ensure that the UK can translate its leadership in quantum research and early-stage innovation into long-term prosperity.”

To accelerate that process the Quantum Cluster announced a strategic partnership with Quantum Exponential, the first UK-based venture capital fund to be entirely focused on quantum technologies. Ian Pearson, the non-executive chairman of the Quantum Exponential, explained that the company is working to generate an investment fund of £100m by the end of 2027 that will support quantum companies as they commercialize their technologies and scale up their businesses. “Now is the time for investment into quantum sector,” said Pearson. “A specialist quantum fund with the expertise needed to analyse and price deals, and to do all the necessary due diligence, will attract more private investment that will help UK companies to grow and scale.”

Around two-thirds of the investments will be directed towards UK-based companies, and as part of the partnership Quantum Exponential will work with the Quantum Cluster to identify and support high-potential quantum businesses within the Harwell Campus. The Quantum Cluster will also play a crucial role in boosting investor confidence – particularly in the unique ability of the Harwell Campus to nurture successful technology businesses – and making connections with international innovation networks to provide UK-based companies with improved access to global markets.

“This new cluster strengthens our national capability and sends a clear signal to global investors that the UK is the place to develop and scale quantum technologies,” commented Michael Cuthbert, Director of the NQCC. “It will help to ensure that quantum innovation delivers benefits not just for science and industry, but for the economy and society as a whole.”

The post Quantum cluster targets business growth appeared first on Physics World.

+ Artificial blood vessels grow with the help of mechanical forces + https://physicsworld.com/a/artificial-blood-vessels-grow-with-the-help-of-mechanical-forces/ + Wed, 12 Aug 2026 08:00:16 +0000 + + + + + https://physicsworld.com/?p=129728 + New technique could allow for the scalable production of vascular tissue networks for regenerative medicine

The post Artificial blood vessels grow with the help of mechanical forces appeared first on Physics World.

Transparent and insulating aerogel could boost energy efficiency of windows

No Author — Thu, 18 Dec 2025 12:07:46 +0000

NASA’s Transiting Exoplanet Survey Satellite (TESS) mission has notched up its first discovery of an exoplanet via a method known as microlensing. The planet is a “super Jupiter” known as Gaia23bra b, and TESS observed it when the planet and its host star acted as a gravitational lens, magnifying the light from a second, more distant background star.

Astronomers have several ways of finding planets beyond our solar system. The most successful of these by far – and the one that TESS was designed for – is the transit method, which is responsible for roughly 75% of all exoplanet detections to date. This approach relies on observing the periodic dimming of a star’s light as a planet passes between the star and an observer here on Earth.

The transit method does have limitations, however. The main limitation is that we can see transits for only a small number of planets, namely those with orbital planes that are almost exactly edge-on to Earth. An alternative approach known as photometric microlensing is somewhat more flexible in this respect, as it relies on the star-planet system magnifying the light from a background star, which is known as the source. This magnification occurs because the gravitational pull of the planet-star system warps space, bending and magnifying the source’s light (as Albert Einstein predicted as part of his general theory of relativity) like a lens and producing characteristic spikes in its brightness.

A second bite at the exoplanetary cherry

Astronomers initially identified a planet in the Gaia23bra system using observations made in 2023 by the European Space Agency’s now-retired Gaia space telescope. However, while Gaia picked up the unexpected brightening of a background star, it did not identify this event as coming from a binary-star system, and it could not pick out the planet itself because its observations were too sparse, explains Mallory Harris, an astronomer at the University of New Mexico, US who led the TESS study.

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In the new work, Harris and colleagues scoured TESS data from the same period. Because TESS’ observations were much denser – it observed the region every 200 seconds for nearly 60 days – they were able to identify extra features in the brightness of the light curve that indicated the presence of a planet in the system. Subsequent analyses revealed that this planet is about 1.63 times the size of Jupiter, and it orbits its host – an orange dwarf star 20% smaller than our Sun – at a distance similar to that of Jupiter from our Sun.

Complementary techniques

The transit technique is particularly sensitive to planets that orbit close to their star because these planets are the most likely to transit and block out most of their host stars’ light as they pass in front of them. In contrast, Harris explains that microlensing is most sensitive to planets orbiting at Earth-like distances or further from their stars, making it better for studying planetary systems more like our own solar system. “With microlensing, we can find smaller planets with greater orbital distances, including worlds in the habitable zone of their star and even farther away,” she says.

The transit technique and microlensing are therefore complementary because each reveals a category of planet that the other may not be able to detect, adds team member Diana Dragomir. The only problem, Harris notes, is that microlensing observations are limited-time opportunities. “Microlensing events happen once and they’re gone – they don’t repeat,” Harris says. “I like to joke that we’ll probably find the first Earth analogue with microlensing and then wave at it as it goes by because we’ll never see it again.”

That said, Harris says that Gaia23bra will be an important observing target for the Nancy Grace Roman Space Telescope. “Microlensing is currently the only method capable of detecting Earth‑mass planets at Earth‑like orbital distances,” she explains. “We already knew that this technique could find planets, because it has done so in the past using ground-based observatories.

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“What we demonstrated in this work is that high-cadence observations (even with low spatial precision) and high-precision long-baseline observations can work together to find a microlensing planet. And that it is possible to specifically do this by pairing TESS observations with those from another instrument.”

This synergy between long-time-scale surveys and high cadence observations could be therefore applied towards future searches for potentially habitable worlds, she tells Physics World. Although Gaia was retired last January, making it unlikely that astronomers will find many additional events via a Gaia–TESS combination, Harris adds that there could nevertheless be other microlensing planets in the past eight years of archived TESS observations. “I’m excited to see whether there are other events like this already hiding in the TESS data and whether future surveys can work together with TESS to find more microlensing planets in different parts of the galaxy,” she says.

The post Transit-based exoplanet survey finds its first microlensing exoplanet appeared first on Physics World.

Qubit ‘recycling’ gives neutral-atom quantum computing a boost

Anna Demming — Thu, 18 Dec 2025 09:00:25 +0000

Black hole collisions, merging neutron stars, exploding supernovae – these massive cosmic events are all observed by interferometer-based gravitational-wave observatories such as LIGO. Detection of the ripples in space-time caused by these phenomena is dependent on the careful control of the mirrors used in these observatories.

Led by Jonathan Richardson at University of California, Riverside, a research team has demonstrated a new wavefront actuator that can correct deformations in the surface of the mirrors by applying carefully mapped heating patterns. In a new development, reported in Classical and Quantum Gravity, Richardson’s team has used thermal imaging cameras to pinpoint where the corrections are needed. This approach should massively reduce the main limitation on the sensitivity of gravitational-wave observations.

Limiting LIGO

Since their first detection in 2015, the world of gravitational-wave observation has thrived. Now, with two major updates planned for pioneer interferometer observatory LIGO (LIGO A+ and LIGO A#) and plans for a more powerful generation of new sites, the field has reached a major turning point. Richardson describes this transition as moving from “an initial discovery era – a time when the closest, loudest events were just barely resolvable above the detectors’ noise floors – to an era of precision science”.

View from above An overhead view demonstrates the immense scale of LIGO’s Livingston site. (Courtesy: Caltech/MIT/LIGO Lab)

Richardson notes that, even now, observations such as that of a binary black hole merger with a record signal-to-noise ratio of 80 are allowing researchers to test our most fundamental theories of the nature of gravity and black holes. Heightened sensitivity will allow the observation of waves that have travelled far greater distances, over longer time periods, and are weaker as a result. These new developments will allow astrophysicists to peer further out into our universe and further back in cosmic time than ever before.

This major increase in sensitivity requires new levels of power, with LIGO A# reaching an unprecedented 1.5 MW of circulating laser arm power. The mirrors used in these detectors absorb some of the power of the incident lasers as thermal energy, resulting in heat-induced distortions that have a detrimental effect on the sensitivity of the detector. It is these deformations that place a limiting factor on the capabilities of gravitational-wave observatories.

A surprisingly simple solution

Richardson’s team has already taken huge steps towards reducing this effect with the development of new adaptive optics. In principle, these devices can apply a variable blanket of heat across the surface of the mirror that cancels out the thermal deformation from the laser heating at the nanoscale. Unfortunately, the application of this method is limited by researchers’ ability to precisely map these aberrations. This lack of sensing capability posed a roadblock on the path to high-powered gravitational-wave observation.

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Richardson’s group discovered a solution to this problem when testing this new technology on a full-scale 40 kg LIGO mirror. They realised that they could accurately reconstruct the optical distortions across the entire 34 cm-diameter mirror by combining direct measurements of the surface temperature with a well programmed model of heat flow in the material.

In a surprising turn of events, the thermal imaging cameras needed to survey the full aperture of the mirror are widely commercially available and can be calibrated using LIGO’s Hartmann wavefront sensors that are already in place. Without the need for a lengthy process of technology development, as is usually required to solve LIGO instrumentation problems, Richardson is “all the more hopeful that we will reach megawatt-scale interferometry in the coming years”.

The future of gravitational-wave detection

The planned improvements to LIGO will drastically increase the observational power of this leading facility, but designs for a new generation of observatories could present even greater opportunities.

Cosmic Explorer is the US-led contribution to a new class of interferometers. Its arms will reach an enormous 40 km each, with ten times the sensitivity of LIGO. Richardson’s team will be responsible for implementing their cutting-edge research in laser wavefront sensing and correction as part of Cosmic Explorer’s base design. As a testing ground for these developments, LIGO will pave the way for an exciting new era of gravitational-wave detection.

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With these levels of sensitivity, Cosmic Explorer aims to observe gravitational waves from hundreds of thousands to millions of black hole and neutron star mergers per year. Gravitational-wave detection will then reach close to the edge of our observable universe, looking back approximately 14 billion years across cosmic time.

Using existing, widely available technology, Richardson’s research group is pushing the limits of gravitational-wave detection and spurring on the development of a new, more powerful class of observatory.

The post Thermal imaging technique helps overcome a major problem for gravitational-wave astronomy appeared first on Physics World.

Forging a more inclusive new generation of physicists

James Dacey — Wed, 17 Dec 2025 18:00:50 +0000

Cold to hot: A visualization of using a quantum switch to implement anomalous heat flow. (Courtesy: Giulio Chiribella, Rosario Lo Franco and Zhong-Xiao Man)

Heat flows from hot objects to cold objects – or does it? Although unidirectional heat flow is a natural consequence of the second law of thermodynamics, which states that entropy must either increase or stay the same, an international team has experimentally demonstrated that a quantum mechanism can reverse this flow of heat while remaining consistent with the laws of thermodynamics. The team then used the same mechanism to design a quantum engine that acts as a refrigerator while simultaneously extracting work.

The demon in the details

Imagine two chambers of gas side by side, separated by a permeable membrane. If the gas in one chamber is hotter than the other, then as time passes, more particles from the hotter chamber will move to the cooler chamber than vice-versa and heat will flow from the hotter chamber to the cooler one.

Now imagine a small agent, or “demon”, standing next to the partition. What if the demon allows cold gas particles to move into the hotter chamber, but stops the hot gas particles from moving to the colder chamber? In this scenario, we have achieved something called anomalous heat flow: the transfer of heat from a cold object to a hot object.

But there’s a catch. For the demon to accomplish this task, it must have a finite memory. That means that eventually, its memory will need to be erased before it can store new information. And it turns out that the erasure of this memory, even when combined with the anomalous heat flow, increases the total entropy. Thus, the second law is not violated.

Causality and the quantum switch

How can one realize such a demon? In the latest work, which is published in Physical Review Letters, Giulio Chiribella, Enrico Russo and Rosario Lo Franco worked with Zhong-Xiao Man and colleagues at Qufu Normal University in China to show that a quantum mechanical tool could perform the task of such a demon experimentally.

Quantum ideas: Team members Enrico Russo, Giulio Chiribella and Rosario Lo Franco. (Courtesy: Enrico Russo, HKU Faculty of Engineering and @onimicphotos)

In quantum mechanics, things don’t need to be in a definite state all the time. They can be in a superposition of multiple states. For instance, a cat in a box can be both dead and alive at the same time until you open the box (perform a measurement). Then the cat’s wavefunction “collapses” into a definite state of either dead or alive.

Similarly, quantum mechanics also allows superpositions in the order of events. In the classical world, event A might happen before event B or vice versa. However, in quantum mechanics, we can instead have a scenario where the orders of operations are in a superposition. This indeterminate sequence of events is known as indefinite causal order, and it was crucial for achieving anomalous heat flow.

“The direction of heat exchange is not determined only by temperatures,” explains Man, a physicist who studies quantum information and quantum optics at Qufu. “When the order of two thermalization processes is coherently controlled, a quantum system can show heat flows that would be impossible in an ordinary classical picture.”

Experimental implementation

The team implemented this control using a device called a quantum switch that has an extra input known as the control quantum bit, or qubit. If the control qubit is in a 0 state, the order of operations is A followed by B. If it is in a 1 state, the order of operations is reversed (B followed by A). However, because the control qubit is a quantum object, it can also be in a superposition of the 1 and 0 state, just like the cat in a box. It is this superposition that implements indefinite causality.

Experimental team: (left-right) Qi Zhang, Xu-Cai Zhuang, Zhong-Xiao Man and Qing-Feng Xue in their lab at Qufu Normal University (Courtesy: Wen-Zhen Li/Qufu Normal University)

To create this quantum switch, the experimentalists in the team used an interferometer to put light in a superposition of two different paths, with the photons experiencing a different order of events in each path. “A photonic set up…reproduces the effect of a quantum switch with modest resources,” explains Chiribella, a quantum information theorist at the University of Hong Kong.

The team also used this set-up to build a version of an engine that transfers heat from a cold body to a hot body while performing work. This is counterintuitive, given that in one framing of the second law of thermodynamics, heat transfer from a cold to hot body must be accompanied by work being done on the engine (rather than being done by it). However, the experiment didn’t break the second law because the control qubit of the quantum switch behaves like the memory of the demon. At the end of each engine cycle, the control qubit must be reset to its initial superposition state. In totality, the second law is obeyed.

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“One of the most exciting aspects of this work is that a highly counterintuitive thermodynamic effect can be explored with photons in an optical laboratory,” observes Lo Franco, a quantum physicist in the Department of Engineering of the Università degli Studi di Palermo, Italy. “This makes the result not only conceptually interesting, but also experimentally accessible and relevant for future quantum technologies.”

The post Quantum principle allows heat to flow from cold to hot appeared first on Physics World.

Why physics should move beyond prestige in PhD admissions

No Author — Mon, 10 Aug 2026 10:00:22 +0000

Physics faces a persistent and uncomfortable paradox. While we repeatedly assert that scientific excellence depends on creativity, rigour, resilience and collaborative problem-solving, the way we select the next generation of researchers still relies heavily on institutional prestige, grades and prior access to opportunity. Although easy to use, these criteria are deeply entangled with structural advantage resulting in a system that is efficient to operate and familiar – yet systematically exclusionary.

Traditional admissions criteria are heavily shaped by unequal access to resources, inside knowledge, mentors and cultural capital
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Most academics recognize the limitations of traditional admissions criteria, but we continue to rely on them. Degree classification, university ranking, publications and reference letters feel like comfortable objective indicators of merit. In reality, however, they are heavily shaped by unequal access to resources, inside knowledge, mentors and cultural capital.

Two students with equal underlying potential, for example, can present very different CVs depending on whether they had access to a research-intensive institution, informal advice networks, paid research internships, or simply, the financial security to take risks. When admissions panels default to these signals as primary filters, they are not solely selecting for ability – they are also selecting for accumulated advantage.

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This is not merely a matter of fairness but a strategic problem for science. Science and technical subjects in the UK face chronic recruitment and retention challenges. At the same time, major issues facing our society are too complex to solve from a single perspective. Physics skills are in growing demand across the UK and Ireland with PhD graduates entering industry, policy, entrepreneurship, education and beyond. This demands not only technical brilliance, but adaptability, communication and ethical judgement.

To achieve the interdisciplinary breadth required to tackle today’s issues, we need to implement thoughtful strategies and processes. If we continue to draw from a narrow and self-reproducing talent pool, we constrain not only who gets to participate in science, but the kind of science we are able to do.

A new approach

At the Centre for Doctoral Training (CDT) in Diversity-Led, Mission-Driven Research (DiveIn) based at the University of Glasgow, we saw an opportunity to move away from PhD admissions criteria being focused on prior privilege towards one based on demonstrable competencies relevant to excellent research and successful completion of a PhD. While most PhD programmes recruit students to predefined projects, which rewards prior disciplinary alignment and insider knowledge, DiveIn instead recruits a cohort first and co-creates projects later.

We worked with the Equity in Doctoral Education through Partnership and Innovation (EDEPI) programme to design a CDT with this mind. EDEPI was created to tackle persistent inequalities that create barriers to access and participation for racially minoritized groups. The EDEPI framework identifies three broad areas: comprehension and evaluation (analytical and problem solving, communication, planning and organization); delivering results (integrity, working with others, independence); and socio-emotional competencies (motivation, curiosity, resilience). We expanded the EDEPI framework to emphasize an appetite for interdisciplinary research; cohort-based development; and advocacy.

A core pillar of the DiveIn approach to the EDEPI framework is anonymization. Our applications are divided into separate components, with personal data, CVs and competency statements de-linked during evaluation. Assessors also never see names, genders, nationalities or institutional affiliations.

The DiveIn admissions process consists of four key elements. The first is an anonymized, competency-based written application, structured around five targeted questions probing motivation, resilience, curiosity and self-reflection. The second is a task-based exercise, in which all applicants analyse the same dataset and explain their reasoning – testing analytical thinking and communication independently of discipline.

Another aspect of the process is a double-marked, wide-ranging assessment, ensuring that no single impression dominates and that different aspects of the application are judged independently. The final aspect is a transparent, structured interview with questions shared in advance and mapped explicitly to competencies.

Applicants are assessed for their ability to thrive in a diverse, collaborative cohort
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Importantly, applicants also receive active support, which includes webinars explaining the process, guidance videos for each question and live drop-in sessions. This is not coaching for advantage – it is an explicit attempt to dismantle the “hidden curriculum” that privileges those already familiar with academic selection rituals. Applicants are, therefore, assessed not only for individual PhD readiness, but for their ability to thrive in a diverse, collaborative cohort.

Diversity gains

DiveIn’s first full recruitment cycle provides some encouraging evidence that our approach is working. The resulting cohort is naturally diverse in background, discipline and experience. Our results also suggest that undergoing such a shift can widen participation without lowering standards and may, in fact, improve the quality and impact of the research that the PhD cohort carry out. In other words, the process did not abandon standards but changed what those standards were designed to measure.

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If we continue to admit PhD candidates primarily based on narrow retrospective signals, we will systematically under-select precisely the kinds of researchers the future requires. Conversely, if we treat admissions as a design problem – something that can be structured, tested, iterated and improved – we open the door to a more resilient, creative and socially responsive generation of researchers. As diversity gains in the technology sector are stalling, this reform to admissions could help sustainably boost diversity in UK Tech.

We can build systems that are fairer, more principled, and more aligned with the realities of modern research
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We now need to refine, scale and continue to evaluate the programme. But the core insight is robust: we can do better than prestige-driven selection. We urge anyone who selects PhD students for their programme to think about these issues and make use of the resources available at EDEPI on inclusive PGR admissions. We can build systems that are fairer, more principled, and better aligned with the realities of modern research.

For a discipline built on careful measurement and experimental design, it is striking how little physics has applied those principles to choosing who gets to become a scientist. Perhaps it is time we did.

This article was written with Ross Forgan, Sandra Dopico Ardao, Qammer Abbasi and Caroline Gauchotte-Lindsay.

The post Why physics should move beyond prestige in PhD admissions appeared first on Physics World.

Learning through laughter at Quantum Carousel

Andrey Feldman — Wed, 17 Dec 2025 16:00:24 +0000

A radio signal has been amplified by scattering it from a stationary coin-sized electronic circuit that behaves as though it is rotating at an enormous rate. Conceived by a team at the City University of New York, the experiment is said to provide the first observation of rotational super-radiance involving electromagnetic waves. This wave-amplification effect is inspired by rotating black holes and was predicted more than half a century ago. Andrea Alù and colleagues found that only radio waves carrying a particular kind of twist were boosted, by as much as a factor of six in power.

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In 1969 Roger Penrose pointed out that a rotating black hole holds a vast reservoir of energy that, in principle, can be tapped. “An object entering the region around the black hole can split into two parts, one falls into the black hole while the other escapes with more energy than the original object had, effectively taking some rotational energy from the black hole,” Alù, explains.

Two years later the Soviet physicist Yakov Zel’dovich realized that the same thing should happen to waves. “If a wave carrying angular momentum reflects from a rapidly rotating absorbing cylinder, the reflected wave could be amplified and come back stronger than it arrived,” says Alù. That amplification is called rotational super-radiance, which Alù describes as, “a process in which a wave becomes stronger by extracting energy from a system that rotates very rapidly”.

The catch has always been the word “rapidly”. For the effect to occur, the rotation must outrun the wave itself, and for light or radio waves that means rotational rates no mechanical object could survive. The effect has been coaxed out of water waves swirling around a vortex and out of sound waves bouncing off a spinning absorber, but electromagnetic waves had been out of reach. “While the idea is fascinating, no experimental demonstration was reported for electromagnetic waves, due to the required very fast speeds,” Alù says.

Clever solution

The CUNY team has found a clever way around the speed restriction. “Instead of physically spinning an object, we created an artificial rotation by periodically changing the properties of a network of resonators in space and time in a way that mimics rotation,” says Alù. The new device is disarmingly simple, comprising three small electrical circuits wired into a loop roughly two centimetres across, each one tuneable like a radio dial. The tuning of all three is wobbled up and down, with each kept slightly out of step with its neighbours, so the pattern sweeps around the loop like a wave passing through a stadium crowd.

“Although no physical object is rotating, this travelling modulation pattern acts like a rotating system,” Alù explains. And because the apparent speed is set purely by how quickly the electronics are driven, it can be pushed as high as one likes. “In fact, this speed can be faster than the velocity of light without violating any physical law.” Nothing material moves, so nothing outruns light.

The researchers fed a 100 MHz radio signal into the loop. This light was in a specific twisted state (possessing orbital angular momentum). They then swept the rotational rate from 5 MHz up to 195 MHz. Below 100 MHz the reflected light weakened steadily, as expected. Above 100 MHz, however, the synthetic rotation overtook the wave and the behaviour flipped. The reflected signals reappeared at the same frequencies as before — 60, 70 and 80 MHz — but were twisted the opposite way, and were stronger rather than weaker. That reversal, Alù notes, is “a key signature of entering the regime associated with super-radiance”. The gain arises in special windows the team calls angular-momentum bandgaps, which open once the synthetic rotation is fast enough and through which “energy can be transferred from the synthetic rotation to the wave”.

Fussy amplfier

The amplification was fussy about its input. “Our observed amplification was selective to the angular momentum of the input wave, only waves with particular angular-momentum properties experienced gain,” says Alù. Stranger still, the effect feeds on waste. In an ordinary amplifier, energy leaking out of the device is the enemy. Here a leakier circuit gave more gain, exactly as the thermodynamic reasoning behind super-radiance demands.

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Alù is careful about what the experiment does and does not deliver. “The experiment does not study actual black holes or quantum gravity. Instead, it creates a laboratory system that reproduces some of the same physical principles involved in rotational energy extraction.” What it offers, he says, is “a controllable analogue platform where researchers can test and explore concepts that are otherwise difficult or impossible to study experimentally in astrophysical black holes”.

Three circuits in the loop allow only three distinct twists, so the immediate goal is bigger loops supporting a wider range. Beyond that lies the jump from radio waves to visible light, and a quantum version in which synthetic rotation might conjure photons out of empty space. Practical spin-offs may arrive sooner. Amplifying only one twist at a time is a natural fit for encoding information, and, Alù suggests, “new forms of lasers, with selective emission of angular momentum, can be envisioned”.

The research is described in Nature.

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Quiz of the week: what age of science is the US entering according to Trump?

No Author — Fri, 07 Aug 2026 15:00:31 +0000

Quantum physics, kung-fu, LEGO and singing are probably not things you would normally put together. But that’s exactly what happened at this year’s Quantum Carousel.

The event is a free variety show where incredible performers from across academia and industry converge for an evening of science communication. Held in Bristol, UK, on 14 November 2025, this was the second year the event was run – and once again it was entirely sold out.

As organizers, our goal was to bring together those involved in quantum and adjacent fields for an evening of learning and laughter. Each act was only seven minutes long and audience participation was encouraged, with questions saved for the dinner and drinks intervals.

All together now Speakers at Quantum Carousel 2025, which was organized by Zulekha Samiullah (second from right) and Hugh Barrett (far right). (Courtesy: Yolan Ankaine)

The evening kicked off with a rousing speech and song from Chris Stewart, motivating the promotion of science communication and understanding. Felix Flicker related electron spin rotations to armlocks, with a terrific demonstration on volunteer Tony Short, while Michael Berry entertained us all with his eye-opening talk on how quantum physics has democratized music.

PhD student double act Eesa Ali and Sebastien Bisdee then welcomed volunteers to the stage to see who could align a laser fastest. Maria Violaris expertly taught us the fundamentals of quantum error correction using LEGO.

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Mike Shubrook explained the quantum thermodynamics of beer through stand-up comedy. And finally, John Rarity and his assistant Hugh Barrett (event co-organizer and co-author of this article) rounded off the night by demonstrating the magic of entanglement.

Our event sponsors introduced the food and drinks portions of the evening, with Antonia Seymour (chief executive of IOP Publishing) and Matin Durrani (editor-in-chief of Physics World) opening the dinner interval, while Josh Silverstone (founder and chief executive of Hartley Ultrafast) kickstarted the networking drinks reception.

Singing praises

Whether it was singing along to an acoustic guitar or rotating hands to emulate electron spin, everyone got involved, and feedback cited audience participation as a highlight.

“The event ran very smoothly, it was lots of fun and a great chance to network in a relaxed atmosphere,” said one attendee. Another added: “The atmosphere was really fun, and it was a really nice event to get loads of the quantum community together in an enjoyable setting.”

Appreciation of the atmosphere went both ways, with one speaker saying that their favourite part of the night was that “the audience was very inviting and easy to perform to”.

Audience members also enjoyed developing a better understanding of the science that drives their industry. “I understood it and I don’t have any background in physics,” said one attendee. “I feel a marker of being a good scientist is being able to explain it in layperson’s terms.”

Reaching out

With the quantum community rapidly expanding, it needs people from a wide range of backgrounds such as computer science, engineering and business. Quantum Carousel was designed to strike a balance between high-level academic discussion and entertainment through entry-level talks, such as explaining error correction with props, or relating research to impact from stimulated emission to CDs.

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By focusing on real-world analogies, these talks can help newcomers to develop an intuitive and memorable understanding. Meanwhile, those already in the field can equip themselves with new ways of communicating elements of their research.

We look forward to hosting Quantum Carousel again in the future. We want to make it bigger and better, with an even greater range of diverse acts.

But if you’re interested in organizing a similar outreach event of your own, it helps to consider how you can create an environment that can best spark connections between both speakers and attendees. Consider your audience and how your event can attract different people for different reasons. In our case, this included the chance to network, engage with the performances, and enjoy the food and drink.

Quantum Carousel was founded by Zulekha Samiullah in 2024, and she and Hugh Barrett now co-lead the event. Quantum Carousel 2025 was sponsored by the QE-CDT, IOP Publishing and Hartley Ultrafast.

This article forms part of Physics World‘s contribution to the 2025 International Year of Quantum Science and Technology (IYQ), which aims to raise global awareness of quantum physics and its applications.

Stayed tuned to Physics World and our international partners throughout the year for more coverage of the IYQ.

Find out more on our quantum channel.

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+ + + https://physicsworld.com/?p=129691 + Have you been keeping up to date with physics news? Try our short quiz to find out

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AI model helps physics Nobel laureate out of a decade-old mathematical jam

Isabelle Dumé — Fri, 07 Aug 2026 13:19:17 +0000

Two theoretical physicists – including a Nobel laureate – have solved a mathematical problem that flummoxed them for 10 years with help from Claude, the large language model (LLM) developed by the US-based firm Anthropic. In addition to its importance for fundamental physics, the result is significant because it offers further evidence that artificial intelligence (AI) is reshaping the nature of research in some fields.

The problem that kept Francesco Zamponi and Giorgio Parisi awake at night originates in the field of complex systems and relates to a phenomenon known as jamming. “Jamming describes a sudden transition at which a fluid system becomes completely rigid, yet remains disordered,” explains Zamponi, a physicist at the Sapienza Università di Roma, Italy.

To visualize this, Zamponi suggests imagining a box filled with spheres (such as tennis balls) that are floating in zero gravity, free from friction or weight. When there are only a few spheres in the box, they have plenty of room to move, bouncing off each other and the box like a classical gas. However, if you add more spheres or inflate the existing ones, space becomes increasingly scarce, and a sphere that tries to move soon impinges on its neighbours. Eventually, a critical density is reached, and every sphere is securely held by those around it, causing the entire system to “lock up” into a state where no more movement is possible.

If the spheres freeze into a regular, geometric pattern, they form a crystal-like structure that resembles carefully stacked oranges at the market. If they are compressed or added quickly, though, a crystal cannot form. Instead, they freeze into a completely disordered packing state, like a traffic jam.

Generalizing the problem

Moving beyond physical spheres into more abstract territory, Zamponi notes that jamming is an example of a highly general mathematical problem known as constraint satisfaction. “In this framework, the spatial positions of the spheres act as the variables, or degrees of freedom, while the strict rule that no two spheres can overlap serves as the constraint,” he explains. As more variables are incorporated, Zamponi adds, satisfying all the rules simultaneously becomes increasingly difficult.

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Because of this precise mathematical mapping, jamming concepts are widely applied in neuroscience and artificial intelligence. In a machine learning model or a biological brain, for example, the synaptic weights represent the degrees of freedom, while the data classifications or memories that must be learned serve as the constraints.

“Just like physical spheres, an artificial neural network undergoes a jamming transition,” Zamponi observes. “In the ‘liquid’ phase, the network easily configures its weights to satisfy all constraints, allowing it to classify data perfectly. But when tasked with too much data, it hits a wall, corresponding to the ‘solid’ phase. It can then no longer satisfy all the conditions, and it begins to make errors.”

A surprising relation

In 2014, Parisi, who received half of the 2021 Nobel Prize in Physics for “the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales”, and Zamponi spotted a surprising relation in the theory of jamming. Working with colleagues in the US and France, they found that in numerical calculations, two mathematical parameters, denoted a and b and related to the scaling of the distribution of contact forces and inter-sphere gaps as the system reaches the jamming point, mysteriously add up to 1. These parameters are very important for characterizing the physical structure of the packing, but try as the researchers might, they could not obtain a formal mathematical proof that a + b = 1.

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Asking generative AI for help was Parisi’s idea. The problem was well-suited for machine assistance because it was well-defined, with a clear conjecture and a known numerical answer but no analytical proof. He and Zamponi chose Claude because it boasts more advanced coding and mathematical reasoning capabilities than other models of its kind.

Even so, they didn’t ask it for the proof immediately. “We first prompted Claude to replicate the numerical calculations our group had developed a decade ago,” Zamponi explains. “Once it had successfully reproduced those exact results, we took the natural next step and asked it: ‛If a + b = 1, can you prove why?’”

The model produced an initial conceptual path that was essentially correct, but that contained minor mathematical errors and required several iterative refinements and verifications. Still, Zamponi says, the “core intuition” belonged to the AI: “We had spent years looking for a complicated solution – like deeply hidden structural symmetry – but Claude showed us that the solution was far simpler; it was right there in front of us, but we had just missed it.

“The new proof connects our infinite-dimensional theory, which is more abstract but mathematically rigorous, with a framework developed at the same time by our colleague Matthieu Wyart and his team at the École Polytechnique Fédérale de Lausanne (EPFL),” Zamponi continues. “Wyart’s theory is built on more concrete physical notions, but it relies nevertheless on some assumptions.” The new result, he tells Physics World, confirms that both starting points lead to the same physical laws.

“More important than the industrial revolution or the birth of the Internet”

Zamponi believes that the advent of generative AI could be on par with, or even more important than, the industrial revolution or the birth of the Internet. As a “telescope for the mind”, he says it could become indispensable for research, allowing scientists to test ideas at unprecedented speeds. It could also lower specialization barriers and facilitate interdisciplinary work by unlocking complex literatures that would otherwise take too long to master.

On the downside, though, Zamponi is concerned that LLMs also encourage the production of poor-quality, pseudo-scientific research, straining the peer-review system. “We desperately need to figure out how to filter and review this influx,” he says. “We also need to design novel pedagogical frameworks to responsibly integrate tools like Claude into undergraduate and graduate research courses.

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“To use these tools responsibly, we believe transparency is key. This is why we chose to publish our full conversation with Claude alongside our paper. If an AI sparks a genuinely new idea, we believe that its ‘thought processes’ should be public record.”

Jamming and random sequential absorption

Zamponi is now applying the approach detailed in the new work, which is published in Journal of Statistical Mechanics: Theory and Experiment, to a problem involving the random sequential absorption (RSA) of hard hyperspheres. This classic protocol for generating random packings involves introducing spheres one by one at completely random positions. “It is a vital tool for understanding the geometry of void spaces and packing efficiency, which directly relates to finding optimal error-correcting codes and navigating the mathematical ‘curse of dimensionality’,” Zamponi says.

While both RSA and jamming transitions describe how systems of hard spheres lock up, they represent two fundamentally different physical processes, he explains. In traditional jamming, particles are mobile and fluid and they continuously rearrange and relax until the entire system undergoes a collective, sudden transition into a rigid, solid-like state. RSA, on the other hand, is a strictly out-of-equilibrium, irreversible process where particles never move once placed. RSA therefore reaches a “saturation” limit rather than a true collective jamming transition.

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New material was created in Hiroshima nuclear explosion

Hamish Johnston — Thu, 06 Aug 2026 15:15:04 +0000

One of my favourite books about physics is The Second Kind of Impossible: the Extraordinary Quest for a New Form of Matter by Paul Steinhardt. It chronicles how the physicist and his colleagues established the extra-terrestrial provenance of a mysterious quasicrystal sample and then trekked to its likely place of origin in the Siberian wilderness.

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That sample was first identified by the Italian geologist Luca Bindi, who features throughout the book and specializes in the discovery of new minerals. I was delighted to see that Bindi has a new paper out that identifies a hitherto unknown material. That excitement was tempered by the fact that the alloy was created by the catastrophic nuclear explosion over the Japanese city of Hiroshima.

On this day in 1945, an atomic bomb was detonated at 580 m over the city, creating a fireball where temperatures exceeded 7000 °C. As many as 140,000 people were killed by the bomb, which destroyed about 70% of the city’s buildings.

Rapid condensation

The fireball was a turbulent plasma of vapourized material from the city. This included building materials, metals, soil, water and, we mustn’t forget, some of the city’s residents. The plasma condensed rapidly creating glassy particles of micron–millimetre size that rained down on the Hiroshima area. These “hiroshimaite” particles mostly comprise of calcium, aluminium and silicon and can be found in the sandy beaches of Hiroshima Bay.

“The fireball left behind materials that never existed before,” says Bindi – who is based at the University of Florence. He adds that these hiroshimaites are helping scientists understand how matter behaves under extreme conditions – describing the fireball as a “giant accidental material-science laboratory”.

Unusual structure

In this latest study, Bindi and colleagues in Italy, the US and Switzerland have identified a new metal alloy in a piece of hiroshimaite. The metallic grain is about one micron in size and is a homogenous mixture of six metals and silicon. X-ray diffraction shows that the alloy has an unusual crystal structure. This, along with the alloy’s high silicon content, make it a special material that has never been seen before.

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According to Bindi, the alloy was formed by the condensation of a complex metallic vapour that was created by a range of materials that were caught up in the nuclear fireball. As the fireball cooled rapidy, a tiny droplet of metals and silicon condensed from the plasma. Then as the temperature dropped at an extraordinary rate, the droplet solidified and its metastable crystal structure was frozen in. This violent quenching prevented the alloy from evolving to a more common crystal structure.

This is not the first time that Bindi has found a new material in the debris of a nuclear explosion. A few years ago his was part of a team that discovered a quasicrystal in a piece of trinitite – glassy material that was created in July 1945 by the Trinity nuclear bomb test in New Mexico.

Bindi and colleagues report their results in Science Advances.

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Korea’s long-term strategy for 2D materials: fundamental science is the secret of success

No Author — Wed, 17 Dec 2025 15:03:17 +0000

Scaling up The IBS Center for Van der Waals Quantum Solids (IBS-VdWQS) acts as a catalyst for advances in fundamental materials science and condensed-matter physics. The purpose-built facility is colocated on the campus of POSTECH, one of Korea’s leading universities. (Courtesy: IBS)

What’s the research mission of the IBS Center for Van der Waals Quantum Solids (IBS-VdWQS)?

Our multidisciplinary team aims to create heteroepitaxial van der Waals quantum solids at system scales, where the crystal lattices and symmetries of these novel 2D materials are artificially moulded to atomic precision via epitaxial growth. Over time, we also hope to translate these new solids into quantum device platforms.

Clearly there’s all sorts of exotic materials physics within that remit.

Correct. We form van der Waals heterostructures by epitaxial manipulation of the crystal lattice in diverse, atomically thin 2D materials – for example, 2D heterostructures incorporating graphene, boron nitride or transition-metal dichalcogenides (such as MoS₂, WSe₂, NbSe₂, TaSe₂and so on). Crucially, the material layers are held in place only by weak van der Waals forces and with no dangling chemical bonds in the direction normal to the layers.

These 2D layers can also be laterally “stitched” into hexagonal or honeycomb lattices, with the electronic and atomic motions confined into the atomic layers. Using state-of-the-art epitaxial techniques, our team can then artificially stack these lattices to form a new class of condensed matter with exotic interlayer couplings and emergent electronic, optical and magnetic properties – properties that, we hope, will find applications in next-generation quantum devices.

The IBS-VdWQS is part of Korea’s Institute for Basic Science (IBS). How does this arrangement work?

Moon-Ho Jo “While the focus is very much on basic science, epitaxial scalability is hard-wired into all our lines of enquiry.” (Courtesy: IBS)

The IBS headquarters was established in 2011 as Korea’s first dedicated institute for fundamental science. It’s an umbrella organization coordinating the activity of 38 centres-of-excellence across the physical sciences, life sciences, as well as mathematics and data science. In this way, IBS specializes in long-range initiatives that require large groups of researchers from Korea and abroad.

Our IBS-VdWQS is a catalyst for advances in fundamental materials science and condensed-matter physics, essentially positioned as a central-government-funded research institution in a research-oriented university. Particularly important in this regard is our colocation on the campus of Pohang University of Science and Technology (POSTECH), one of Korea’s leading academic centres, and our adjacency to large-scale facilities like the Pohang Synchrotron Radiation Facility (PAL) and Pohang X-ray free-electron laser (PAL-XFEL). It’s worth noting as well that all the principal investigators (PIs) in our centre hold dual positions as IBS researchers and POSTECH professors.

So IBS is majoring on strategic research initiatives?

Absolutely – and that perspective also underpins our funding model. The IBS-VdWQS was launched in 2022 and is funded by IBS for an initial period through to 2032 (with a series of six-year extensions subject to the originality and impact of our research). As such, we are able to encourage autonomy across our 2D materials programme, giving scientists the academic freedom to pursue questions in basic research without the bureaucracy and overhead of endless grant proposals. Team members know that, with plenty of hard work and creativity, they have everything they need here to do great science and build their careers.

Your core remit is fundamental science, but what technologies could eventually emerge from the IBS-VdWQS research programme?

While the focus is very much on basic science, epitaxial scalability is hard-wired into all our lines of enquiry. In short: we are creating new 2D materials via epitaxial growth and this ultimately opens a pathway to wafer-scale industrial production of van der Waals materials with commercially interesting semiconducting, superconducting or emergent properties in general.

Right now, we are investigating van der Waals semiconductors and the potential integration of MoS₂ and WSe₂ with silicon for new generations of low-power logic circuitry. On a longer timeline, we are developing new types of high-Tc (around 10 K) van der Waals superconductors for applications in Josephson junctions, which are core building blocks in superconducting quantum computers.

There’s a parallel opportunity in photonic quantum computing, with van der Waals materials shaping up as promising candidates for quantum light-emitters that generate on-demand (deterministic) and highly coherent (indistinguishable) single-photon streams.

Establishing a new research centre from scratch can’t have been easy. How are things progressing?

It’s been a busy three years since the launch of the IBS-VdWQS. The most important task at the outset was centralization – pulling together previously scattered resources, equipment and staff from around the POSTECH campus. We completed the move into our purpose-built facility, next door to the PAL synchrotron light source, at the end of last year and have now established dedicated laboratory areas for the van der Waals Epitaxy Division; Quantum Device and Optics Division; Quantum Device Fabrication Division; and the Imaging and Spectroscopy Division.

One of our front-line research efforts is building a van der Waals Quantum Solid Cluster, an integrated system of multiple instruments connected by ultra-high-vacuum lines to maintain atomically clean surfaces. We believe this advanced capability will allow us to reliably study air-sensitive van der Waals materials and open up opportunities to discover new physics in previously inaccessible van der Waals platforms.

Integrated thinking The IBS-VdWQS hosts an end-to-end research programme spanning advanced fabrication, materials characterization and theoretical studies. From left to right: vapour-phase van der Waals crystal growth; femtosecond laser spectroscopy for studying ultrafast charge, spin and lattice dynamics; and an STM system for investigations of electronic structure and local quantum properties in van der Waals materials. (Courtesy: IBS)

Are there plans to scale the IBS-VdWQS work programme?

Right now, my priority is to promote opportunities for graduate students, postdoctoral researchers and research fellows to accelerate the centre’s expanding research brief. Diversity is strength, so I’m especially keen to encourage more in-bound applications from talented experimental and theoretical physicists in Europe and North America. Our current research cohort comprises 30+ PhD students, seven postdocs (from the US, India, China and Korea) and seven PIs.

Over the next five years, we aim to scale up to 25+ postdocs and research fellows and push out in new directions such as scalable quantum devices. In particular, we are looking for scientists with specialist know-how and expertise in areas like materials synthesis, quantum transport, optical spectroscopy and scanning probe microscopy (SPM) to accelerate our materials research.

How do you support your early-career researchers at IBS-VdWQS?

We are committed to nurturing global early-career talent and provide a clear development pathway from PhD through postdoctoral studies to student research fellow and research fellow/PI. Our current staff PIs have diverse academic backgrounds – materials science, physics, electronic engineering and chemistry – and we therefore allow early-career scientists to have a nominated co-adviser alongside their main PI. This model means research students learn in an integrated fashion that encourages a “multidisciplinarian” mindset – majoring in epitaxial growth, low-temperature electronic devices and optical spectroscopy, say, while also maintaining a watching brief (through their co-adviser) on the latest advances in materials characterization and analysis.

What does success look like at the end of the current funding cycle?

With 2032 as the first milestone year in this budget cycle, we are working to establish a global hub for van der Waals materials science – a highly collaborative and integrated research programme spanning advanced fabrication, materials characterization/analysis and theoretical studies. More capacity, more research infrastructure, more international scientists are all key to delivering our development roadmap for 2D semiconductor and superconductor integration towards scalable, next-generation low-power electronics and quantum computing devices.

Find more information on open research positions at IBS-VdWQS.

Building a scientific career in 2D materials

Myungchul Oh “We are exploring the microscopic nature of quantum materials and their device applications.” (Courtesy: IBS)

Myungchul Oh joined the IBS-VdWQS in 2023 after a five-year stint as a postdoctoral physicist at Princeton University in the US, where he studied strongly correlated phenomena, superconductivity and topological properties in “twisted” graphene systems.

Recruited as an IBS-POSTECH research fellow, Oh holds dual academic positions: team leader for the quantum-device microscopy investigations at IBS-VdWQS and assistant professor in the semiconductor engineering department at POSTECH.

Van der Waals heterostructures, assembled layer-by-layer from 2D materials, enable precise engineering of quantum properties through the interaction between different atomic layers. By extension, Oh and his colleagues are focused on the development of novel van der Waals systems; their integration into devices via nanofabrication; and the study of electrical, magnetic and topological properties under extreme conditions, where quantum-mechanical effects dominate.

“We are exploring the microscopic nature of quantum materials and their device applications,” Oh explains. “Our research combines novel 2D van der Waals heterostructure device fabrication techniques with cryogenic scanning probe microscopy (SPM) measurements – the latter to access the atomic-scale electronic structure and local physical properties of quantum phases in 2D materials.”

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+ Building bridges between quantum and classical computing + https://physicsworld.com/a/building-bridges-between-quantum-and-classical-computing/ + Thu, 06 Aug 2026 13:23:38 +0000 + + + + + https://physicsworld.com/?p=129667 + Yonatan Cohen of Quantum Machines is our podcast guest

The post Building bridges between quantum and classical computing appeared first on Physics World.

Atomic system acts like a quantum Newton’s cradle

No Author — Wed, 17 Dec 2025 11:15:48 +0000

Atoms in a one-dimensional quantum gas behave like a Newton’s cradle toy, transferring energy from atom to atom without dissipation. Developed by researchers at the TU Wien, Austria, this quantum fluid of ultracold, confined rubidium atoms can be used to simulate more complex solid-state systems. By measuring transport quantities within this “perfect” atomic system, the team hope to obtain a deeper understanding of how transport phenomena and thermodynamics behave at the quantum level.

Physical systems transport energy, charge and mass in various ways. Electrical currents streaming along a wire, heat flowing through a solid and light travelling down an optical fibre are just three examples. How easily these quantities move inside a material depends on the resistance they experience, with collisions and friction slowing them down and making them fade away. This level of resistance largely determines whether the material is classed as an insulator, a conductor or a superconductor.

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The mechanisms behind such transport fall into two main categories. The first is ballistic transport, which features linear movement without loss, like a bullet travelling in a straight line. The second is diffusive transport, where the quantity is subject to many random collisions. A good example is heat conduction, where the heat moves through a material gradually, travelling in many directions at once.

Breaking the rules

Most systems are strongly affected by diffusion, which makes it surprising that the TU Wien researchers could build an atomic system where mass and energy flowed freely without it. According to study leader Frederik Møller, the key to this unusual behaviour is the magnetic and optical fields that keep the rubidium atoms confined to one dimension, “freezing out” interactions in the atoms’ two transverse directions.

Because the atoms can only move along a single direction, Møller explains, they transfer momentum perfectly, without scattering their energy as would be the case in normal matter. Consequently, the 1D atomic system does not thermalize despite being subject to thousands of collisions.

To quantify the transport of mass (charge) and energy within this system, the researchers measured quantities known as Drude weights, which are fundamental parameters that describe ballistic, dissipationless transport in solid-state environments. According to these measurements, the single-dimensional interacting bosonic atoms do indeed demonstrate perfect dissipationless transport. The results also agree with the generalized hydrodynamics (GHD) theoretical framework, which describes the large-scale, inhomogeneous dynamics of one-dimensional integrable quantum many-body systems such as ultracold atomic gases or specific spin chains.

A Newton’s cradle for atoms

According to team leader Jörg Schmiedmayer, the experiment is analogous to a Newton’s cradle toy, which consists of a row of metal balls suspended on wires (see below). When the ball on one end of the row is made to collide with the one next to it, its momentum transfers straight through the other balls to the ball on the opposite end, which swings out. Schmiedmayer adds that the system makes it possible to study transport under perfectly controlled conditions and could open new ways of understanding how resistance emerges, or disappears, at the quantum level. “Our next steps are applying the method to strongly correlated transport and to transport in a topological fluid,” he tells Physics World.

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Karèn Kheruntsyan, a theoretical physicist at the University of Queensland, Australia, who was not involved in this research, calls it “a significant step for studying quantum transport”. He says the team’s work clearly demonstrates ballistic (dissipationless) transport at a finite temperature, providing an experimental benchmark for theories of integrability and disorder. The work also validates the thermodynamic meaning of Drude weights, while confirming that linear-response theory and GHD accurately describe transport in quantum systems.

+ + + + https://physicsworld.com/?p=129658 + Can you work out the word in this puzzle?

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Astronomers capture highest-resolution image ever of the Sun’s surface

Michael Banks — Thu, 06 Aug 2026 10:50:45 +0000

An international team of astronomers has released the highest-resolution image ever captured of the Sun’s visible surface. Taken by the Daniel K Inouye Solar Telescope in Hawaii, the picture reveals tiny plasma whirlpool-like patterns that have never been seen before (Nature doi:10.1038/s41586-026-10871-3).

The Sun’s visible surface – the photosphere – is a thin layer of its atmosphere where the fluid plasma becomes transparent. This region is known to be dynamic and complex, with factors such as magnetic field and convection currents shaping the atmosphere.

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The studied region by the astronomers is a magnetically active area close to a sunspot. In the image, the solar surface appears dominated by band-like and vortex-like structures.

The authors associate these features with Kelvin-Helmholtz instabilities, a well-known effect in fluid dynamics in which rippled structures form when two fluids slide past each other at different speeds.

This generates shear forces at the interface, causing minute disturbances to grow into wave- or vortex-like flows.

The vortices occur at the edges of so-called granules, which densely cover the Sun’s visible surface and measure between 500 and 2000 km in diameter.

Some of these “fringes” are little more than 20 km wide and resolving these structures is comparable to discerning a €1 coin from a distance of 180 km.

The findings provide the first known confirmation of Kelvin-Helmholtz instabilities on the Sun and researchers suggest that the instability might explain why the Sun’s outer atmosphere gets so hot, and why magnetic energy builds up and moves around the surface.

“The newly discovered plasma vortices impressively demonstrate how minute processes – at the limit of what we can resolve using all available techniques – significantly determine the nature of our star,” notes Sami Solanki, director of the Max Planck Institute for Solar System Research in Göttingen, Germany.

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Topology affects the crumpling of growing elastic sheets

Sam Jarman — Thu, 06 Aug 2026 08:10:45 +0000

More dimples A series of hollow objects made from elastic sheets. The size of the objects increases in the directions indicated by the arrows. The number of buckles in the object is seen to increase as its shape changes. (Courtesy: Yafei Zhang)

A new mechanism governing the geometric shapes of growing elastic sheets has been identified by a trio of physicists in Israel. Through a combination of simulations and experiments, Eran Sharon and colleagues at the Hebrew University of Jerusalem showed that the dimpled patterns that form in a growing elastic object have topological origins.

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This mechanism is unrelated to geometric incompatibilities, which are known to dimple natural materials. The discovery could lead to a deeper understanding of how complex shapes emerge in the natural world – and to the development of new artificial materials.

Thin sheets are ubiquitous in nature: examples include leaves, petals, and the cellular linings of organs and blood vessels. The complex makeup of natural sheets means that local regions within them have preferred mechanical rest states that are incompatible with those of other regions. As a result, there is no way to arrange the sheet so that every part is simultaneously stress free – leading to effects like wrinkling, bending, and buckling.

Called geometric incompatibility, this phenomenon is responsible for numerous geometric forms in the natural world, enabling growing tissues to shape themselves without any external influence. For some time, researchers have attempted to mimic these natural mechanisms in synthetic materials.

Richness of shapes

“Looking at natural growth processes, as in plants growth, or embryo development, we see amazing richness of shapes and shape development that currently cannot be achieved with conventional fabrication methods,” says Sharon.

Sharon’s group has already shown that many patterns in nature can be understood in terms of the Gauss and Mainardi-Codazzi-Peterson incompatibilities – which were developed in the 19^th century. Together with team member Michael Moshe, whose group explores the interplay between mechanics and geometry in soft materials, their work led to discoveries including the mechanical origins of shape selection in rose petals.

Now, Moshe and Sharon have teamed-up with Yafei Zhang to identify a phenomenon that cannot be explained by those mechanical instabilities. In their experiment, they started with a uniform elastic sheet formed into a hollow sphere, with circular holes at each pole. When they added wedges of material into the sheet to mimic growth, it initially behaved like a smooth, growing sphere – but only up to a certain point.

Missing mechanism

“The growing sheet satisfies the established local compatibility conditions, and is thus expected to show smooth ‘boring’ shape,” Moshe explains. “Yet it unexpectedly, develops a crumpled appearance, suggesting that an important shaping mechanism was missing from the existing framework.”

Important clues came when the team cut into the crumpled sphere along a meridian, from pole to pole. Instantly, the crumpling disappeared, and the sphere relaxed back to its original smooth shape. This effect also occurs in simulations of a smoothly growing sphere.

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With no changes to the Gauss or Mainardi-Codazzi-Peterson incompatibilities governing the mechanical forces in the sheet, the trio concluded that the sudden transformation emerged from an entirely different mechanism, rooted in the mathematical principles of topology. In this view, unlike smooth geometric transformations such as bending, stretching, or twisting, which preserve a shape’s mechanical properties, cutting introduces a sudden transformation that changes its mechanical behaviour.

In this way, the meridional cut brought the sphere into a new topological state. “Unlike conventional incompatibility, this frustration is topological in character, and can be quantified by a global measure,” Moshe explains. “It provides a new mechanism by which growing sheets can select complex, wrinkled or dimpled shapes.”

The trio’s discovery now raises new mathematical questions about the limits of growing elastic sheets, beyond which their smooth geometries can no longer be maintained. “What we have discovered that the geometrical principles we knew before should be supplemented with topological considerations, leading to an even wider class of shaping principles,” Sharon says. “This allows a better understanding of morphogenetic processes and expands our abilities to shape synthetic structures.”

In turn, the team’s insights could uncover new understanding of how shaping mechanisms could be harnessed, perhaps leading to the discovery of new metamaterials, with shapes and mechanical functions programmed into their growth.

The research is described in Physical Review Letters.

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Want a strong future for physics? Here’s why we must focus on students from under-represented groups

No Author — Wed, 17 Dec 2025 11:00:50 +0000

Physics students from under-represented groups consistently report a lower sense of belonging at university than their over-represented peers. These students experience specific challenges that make them feel undervalued and excluded. Yet a strong sense of belonging has been shown to lead to improved academic performance, greater engagement in courses and better mental wellbeing. It is vital, then, that universities make changes to help eliminate these challenges.

Students are uniquely placed to describe the issues when it comes to belonging in physics. With this mind, as an undergraduate physics student with a passion for making the discipline more diverse and inclusive, I conducted focus groups with current and former physics students, interviewed experts and performed an analysis of current literature. This was part of a summer project funded by the Royal Institution and is currently being finalized for publication.

From this work it became clear that under-represented groups face many challenges to developing a strong sense of belonging in physics, but, at the same time, there are ways to improve the everyday experiences of students. When it comes to barriers, one is the widely held belief – reflected in the way physicists are depicted in the media and textbooks – that you need to be a “natural genius” to succeed in university physics. This notion hampers students from under-represented groups, who see peers from the over-represented majority appearing to grasp concepts more quickly and lecturers suggesting certain topics are “easy”.

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The feeling that physics demands natural ability also arises from the so-called “weed out” culture, which is defined as courses that are intentionally designed to filter students out, reduce class sizes and diminish sense of belonging. Students who we surveyed believe that the high fail rate is caused by a disconnect between the teaching and workshops on the course and the final exam.

A third cause of this perception that you need some innate ability to succeed in physics is the attitudes and behaviour of some professors, lecturers and demonstrators. This includes casual sexist and racist behaviour; belittling students who ask for help; and acting as if they’re uninterested in teaching. Students from under-represented groups report significantly lower levels of respect and recognition from instructors, which damages their resilience and weakens sense of belonging.

Students from under-represented groups are also more likely to be isolated from their class mates and feel socially excluded from them. This means they lack a support network, leaving them with no-one to turn to when they encounter challenges. Outside the lecture theatre, students from under-represented groups typically face many microaggressions in their day-to-day university experience. These are subtle indignities or insults, unconsciously or consciously, towards minorities such as people of colour being told they “speak English very well”, male students refusing to accept women’s ideas, and the assumption that gender minorities will take on administrative roles in group projects.

Focus on the future

So what can be done? The good news is that there are many solutions to mitigate these issues and improve a sense of belonging. First, institutions should place more emphasis on small group “active learning” – which includes discussions, problem solving and peer-based learning. These pedagogical strategies have been shown to boost belonging, particularly for female students. After these active-learning sessions, non-academic, culturally sensitive social lunches can help turn “course friends” to “real friends” who choose to meet socially and can become a support network. This can help build connections within and between degree cohorts.

Another solution is for universities to invite former students to speak about their sense of belonging and how it evolved or improved throughout their degree. Hearing about struggles and learning tried-and-tested strategies to improve resilience can help students better prepare for stressful situations. Alumni are more relatable than generic messaging from the university wellbeing team.

Building closer links between students and staff also enhances a sense of belonging. It helps humanise lecturers and demonstrate that staff care about student wellbeing and success. This should be implemented by recognizing staff efforts formally so that the service roles of faculty members are formally recognized and professionalized.

Universities should also focus on hiring more diverse teaching staff, who can serve as role models, using their experiences to relate to and engage with under-represented students. Students will end up feeling more embedded within the physics community, improving both their sense of belonging and performance.

One practical way to increase diversity in hiring is for institutions to re-evaluate what they value. While securing large grants is valuable, so is advocating for equality, diversity and inclusion; public engagement; and the ability to inspire the next generation of physicists.

Another approach is to establish “departmental action teams” to find tailored solutions to unite undergraduates, postgraduates, teaching and research staff. Such teams identify issues specific to their particular university, and they can gather data through surveying the department to identify trends and recommend practical changes to boost belonging.

Implementing these measures will not only improve the sense of belonging for students from under-represented groups but also cultivate a more inclusive, diverse physics workforce. That in turn will boost the overall research culture, opening up research directions that may have previously been overlooked, and yielding stronger scientific outputs. It is crucial that we do more to support physics students from under-represented groups to create a more diverse physics community. Ultimately, it will benefit physics and society as a whole.

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+ Critics deride US administration’s ‘golden age of science’ report + https://physicsworld.com/a/critics-deride-us-administrations-golden-age-of-science-report/ + Wed, 05 Aug 2026 10:42:37 +0000 + + + + https://physicsworld.com/?p=129620 + The document comes as the administration looks to cut the science budget for 2027

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Improving precision in muon g-2 calculations

Margaret Harris — Wed, 17 Dec 2025 08:16:58 +0000

Kristian Dominek Barajas is head of quantum theory at the UK-based quantum computing company Oxford Ionics, which merged with the US firm IonQ in 2025. Barajas got his PhD – which was focused on developing analytic methods for high-accuracy models of driven quantum systems beyond the rotating-wave approximation – at the University of California Los Angeles, US, via the American Physical Society’s Bridge Program. The programme provides pathways into research for qualified students who might not otherwise continue their physics education. He now serves as chair of the APS Committee on Minorities (2025–2026), where he helps shape national initiatives that support physicists from historically marginalized backgrounds – particularly people of colour, LGBTQIA+ physicists, and physicists with disabilities.

What skills do you use every day in your job?

Because I’m relatively new to the field, I often have to break difficult questions down into simpler ideas before I can grapple with them. That has trained me to take a really complicated problem and give it my best guess, and that first-pass intuition often gets me surprisingly close to the full solution.

The other thing I’d highlight is leadership skills. I come from an untraditional background – it took me a long time to do my undergraduate degree, and afterwards I worked in a lot of different jobs, including working at a pet store, where I was training to become a team lead. When I went to grad school, I applied through the APS Bridge Program, which is great, and it gave me an opportunity to get into research. But again, my path wasn’t traditional: I did soft condensed matter physics for four years, and then my advisor passed away unexpectedly, so I switched fields to trapped ions because I needed to graduate. I had no background in quantum physics at that point, so it was quite a transition.

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Experiences like this added up. By the time I joined Oxford Ionics right before the merger with IonQ, even though I was the “greenest” person in my team in terms of being new to the field, I had the most leadership experience. That meant I went from being an entry-level quantum theorist to a senior quantum theorist in two or three months. A month and a half later, I became the atomic, molecular and optical (AMO) theory manager. The experience I’d gained made it easy to set priorities and get people to go in the correct direction.

What do you like best and least about your job?

My least favourite part of the job is that I don’t get to read much new research. The job is so fast-paced and there’s so many things happening every day that getting the chance to sit down and read an article is quite rare. I use AI tools to help me find and keep up with new research. Part of my workflow involves asking AI to identify relevant papers and give me an initial sense of what I need to know. I still skim the papers themselves as much as I can, but I don’t get the chance as often as I’d like to pick up a manuscript and spend a whole day working through it like I did in academia.

We also don’t always have the time to write papers about what we’re doing. It’s not that we aren’t allowed to – in fact, we’re encouraged to pursue that if we want to do it – but finding time is challenging.

I’m constantly getting to do new and interesting physics, and I absolutely love that about my job
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The upside is that the pace at which I get to do research far, far outweighs what I experienced in academia. What we accomplish on our team in four to six weeks is comparable to the amount we would do in six months in academia. It is absurd how fast we get to move. I’m constantly getting to do new and interesting physics, and I absolutely love that about my job.

What do you know now that you wish you’d known at the start of your career?

I wish I’d known that feelings of imposter syndrome don’t always have to be something to fear. For me, they can also be a reminder that there is still so much more to learn, and that can be exciting. That’s why I was so excited for the opportunity to earn my PhD in physics: it gave me the chance to keep learning. Now, whenever that old imposter feeling comes up, I try to see it as an opportunity to learn rather than a reason to hold myself back. I wish I had embraced that earlier in my career and not been so afraid to try things.

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Magnetic molecules explain a puzzling material

Lorna Brigham — Wed, 05 Aug 2026 07:04:57 +0000

Na₂Mn₃O₇ is a magnetic material that behaves unusually and therefore can provide insight into how magnetism emerges in complex materials. Magnetic materials contain entities known as spins, which can be thought of as tiny magnets with north and south poles. These spins interact with neighbouring spins, and as a material is cooled, they often align into an ordered pattern that extends across the entire material, known as long-range magnetic order.

However, Na₂Mn₃O₇, which contains magnetic Mn⁴⁺ ions, behaves differently. It has strong magnetic interactions, very little disorder, and a two-dimensional arrangement of magnetic ions. Under these conditions, a material with relatively large spins would normally be expected to develop long-range magnetic order at low temperatures. Surprisingly, no magnetic ordering is observed, even at very low temperatures.

The material also exhibits two distinct magnetic crossovers. Around 110-120 K, the magnetic susceptibility reaches a broad maximum, indicating that strong magnetic correlations are developing. Around 60-70 K, a feature appears in the specific heat, showing that the system is undergoing a further internal reorganisation. The presence of two separate temperature scales suggests that the magnetism develops in two stages.

The crystal structure of Na₂Mn₃O₇ organises the Mn spins into strongly correlated hexagonal units, connected by weaker and frustrated interactions. This hierarchy suppresses conventional magnetic order and produces a molecularized two-dimensional magnetic state. (Courtesy: Iqbal/Indian Institute of Technology Madras)

Using theoretical and computational techniques, the researchers showed that this unusual behaviour originates from the crystal structure of Na₂Mn₃O₇. The crystal structure divides the magnetic lattice into strongly connected hexagonal clusters of six Mn ions. These clusters behave like magnetic ‘molecules’, with the spins inside each hexagon becoming strongly correlated. Interactions between different hexagons are much weaker and frustrated, preventing the formation of long-range magnetic order across the material.

This research is important because it demonstrates that even large-spin magnetic materials can exhibit quantum-disordered behaviour. More broadly, it shows that crystal structure can be used as a tool to engineer new magnetic states by organising spins into strongly correlated clusters that suppress conventional magnetic ordering.

“What is striking in Na₂Mn₃O₇ is that the crystal structure does more than slightly distort the magnetic lattice. It reorganises the spins into strongly correlated hexagons that behave as emergent magnetic molecules, while frustration and quantum fluctuations prevent these units from ordering collectively.“ – Yasir Iqbal, Indian Institute of Technology Madras

Read the full article

Lattice QCD calculation of the π0-pole contribution to the hadronic light-by-light scattering in the anomalous magnetic moment of the muon

Tian Lin et al 2025 Rep. Prog. Phys. 88 080501

Crystallography-driven molecularization of a two-dimensional spin-3/2 magnet

Hari Borutta et al 2026 Rep. Prog. Phys. 89 068003

Do you want to learn more about this topic?

The muon Smasher’s guide Hind Al Ali et al (2022)

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Frustrated magnets in high magnetic fields—selected examples by J Wosnitza, S A Zvyagin and S Zherlitsyn (2016)

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How does quantum entanglement move between different particles?

Paul Mabey — Wed, 17 Dec 2025 08:16:11 +0000

Graphene, an atomically thin material of a single layer of carbon atoms, is a fascinating material for high-speed electronics, spintronic devices, and neuromorphic components due to its exceptional tunable electrical conductivity. One area of research focuses on understanding how electrons flow through graphene to enable the design of advanced devices. For applications, ultrathin metal-oxide layers (e.g., aluminum oxide and titanium oxide) are routinely deposited on graphene, which deliberately alter electron flow and provide greater control over its properties, in devices ranging from transistors to spin valves. However, although the effects of these coatings are known, researchers have not previously been able to directly observe what is happening inside the device. Instead, their understanding has relied primarily on theoretical models, numerical simulations, and indirect electrical measurements.

In this work, the researchers used X-ray Photoelectron Spectroscopy (XPS) to map electrical potentials across devices while they were operating. They examined the electrical landscape, identifying regions with steep slopes corresponding to strong electric fields and flatter regions corresponding to weaker electric fields, to determine how oxide coatings modify this landscape. They found that metal oxides flatten the electrical landscape through a process known as p-type charge-transfer doping. This occurs when the oxide removes some electrons from the graphene, altering its local electrostatic environment and reducing the voltage gradient. As a result, local electric fields become weaker. The oxide layers suppress the electric fields, reducing them by more than 50%, a significant effect for device operation. A key advance of this research is the visualisation of this effect at very high spatial resolution, whereas previously it could only be inferred from electrical resistance measurements. In addition, by making a direct comparison with electrical measurements, the researchers confirmed the observed effects are due solely to electrostatics and charge redistribution.

Spatially resolved scanning photoemission microscopy (SPEM) directly maps the voltage drop across a working graphene device, revealing how metal oxide-covered regions suppress local electric fields in graphene (Courtesy: Umidakhon Rayimjonova and M. Venkata Kamalakar/Uppsala University)

Modern electronic devices increasingly depend on controlling electricity at very small scales. By locally adjusting electric fields using oxide coatings, researchers gain an additional design tool that enables different regions of a graphene circuit to be tuned independently. This is particularly important for spintronic devices, which are highly sensitive to local electric fields, and neuromorphic computing hardware, which requires precise control of local electrical properties.

This work represents a breakthrough in the ability to directly map charge distributions and electric fields inside operating 2D-material devices, enabling improved device design.

Read the full article

Entanglement transfer in a composite electron–ion–photon system – IOPscience

A. Stenquist et al 2025 Rep. Prog. Phys. 88 080502

Direct visualization of field-driven valence band modulation in electrostatically reconfigured graphene devices

Umidakhon Rayimjonova et al 2026 Rep. Prog. Phys. 89 060502

The post How does quantum entanglement move between different particles? appeared first on Physics World.

Do you want to learn more about this topic?

Phonons and thermal transport in graphene and graphene-based materials byDenis L Nika and Alexander A Balandin (2017)

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Motion through quantum space–time is traced by ‘q-desics’

No Author — Tue, 16 Dec 2025 16:19:23 +0000

Physicists searching for signs of quantum gravity have long faced a frustrating problem. Even if gravity does have a quantum nature, its effects are expected to show up only at extremely small distances, far beyond the reach of experiments. A new theoretical study by Benjamin Koch and colleagues at the Technical University of Vienna in Austria suggests a different strategy. Instead of looking for quantum gravity where space–time is tiny, the researchers argue that subtle quantum effects could influence how particles and light move across huge cosmical distances.

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Their work introduces a new concept called q-desics, short for quantum-corrected paths through space–time. These paths generalize the familiar trajectories predicted by Einstein’s general theory of relativity and could, in principle, leave observable fingerprints in cosmology and astrophysics.

General relativity and quantum mechanics are two of the most successful theories in physics, yet they describe nature in radically different ways. General relativity treats gravity as the smooth curvature of space–time, while quantum mechanics governs the probabilistic behavior of particles and fields. Reconciling the two has been one of the central challenges of theoretical physics for decades.

“One side of the problem is that one has to come up with a mathematical framework that unifies quantum mechanics and general relativity in a single consistent theory,” Koch explains. “Over many decades, numerous attempts have been made by some of the most brilliant minds humanity has to offer.” Despite this effort, no approach has yet gained universal acceptance.

Deeper difficulty

There is another, perhaps deeper difficulty. “We have little to no guidance, neither from experiments nor from observations that could tell us whether we actually are heading in the right direction or not,” Koch says. Without experimental clues, many ideas about quantum gravity remain largely speculative.

That does not mean the quest lacks value. Fundamental research often pays off in unexpected ways. “We rarely know what to expect behind the next tree in the jungle of knowledge,” Koch says. “We only can look back and realize that some of the previously explored trees provided treasures of great use and others just helped us to understand things a little better.”

Almost every test of general relativity relies on a simple assumption. Light rays and freely falling particles follow specific paths, known as geodesics, determined entirely by the geometry of space–time. From gravitational lensing to planetary motion, this idea underpins how physicists interpret astronomical data.

Koch and his collaborators asked what happens to this assumption when space–time itself is treated as a quantum object. “Almost all interpretations of observational astrophysical and astronomical data rest on the assumption that in empty space light and particles travel on a path which is described by the geodesic equation,” Koch says. “We have shown that in the context of quantum gravity this equation has to be generalized.”

Generalized q-desic

The result is the q-desic equation. Instead of relying only on an averaged, classical picture of space–time, q-desics account for the underlying quantum structure more directly. In practical terms, this means that particles may follow paths that deviate slightly from those predicted by classical general relativity, even when space–time looks smooth on average.

Crucially, the team found that these deviations are not confined to tiny distances. “What makes our first results on the q-desics so interesting is that apart from these short distance effects, there are also long range effects possible, if one takes into account the existence of the cosmological constant,” Koch says.

This opens the door to possible tests using existing astronomical data. According to the study, q-desics could differ from ordinary geodesics over cosmological distances, affecting how matter and light propagate across the universe.

“The q-desics might be distinguished from geodesics at cosmological large distances,” Koch says, “which would be an observable manifestation of quantum gravity effects.”

Cosmological tensions

The researchers propose revisiting cosmological observations. “Currently, there are many tensions popping up between the Standard Model of cosmology and observed data,” Koch notes. “All these tensions are linked, one way or another, to the use of geodesics at vastly different distance scales.” The q-desic framework offers a new lens through which to examine such discrepancies.

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So far, the team has explored simplified scenarios and idealized models of quantum space–time. Extending the framework to more realistic situations will require substantial effort.

“The initial work was done with one PhD student (Ali Riahina) and one colleague (Ángel Rincón),” Koch says. “There are many things to be revisited and explored that our to-do list is growing far too long for just a few people.” One immediate goal is to encourage other researchers to engage with the idea and test it in different theoretical settings.

Whether q-desics will provide an observational window into quantum gravity remains to be seen. But by shifting attention from the smallest scales to the largest structures in the cosmos, the work offers a fresh perspective on an enduring problem.

The research is described in Physical Review D.

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From building a workforce to boosting research and education – future quantum leaders have their say

Matin Durrani — Tue, 16 Dec 2025 11:15:08 +0000

India has produced some exceptional women physicists over the years. From Bibha Chowdhuri, who co-discovered the meson and became the first Indian woman to receive a PhD in physics, to Ritu Karidhal, who played a pivotal role in making India the fourth country in the world to reach Mars, the country boasts a large pool of talented women.

But despite women accounting for more than 40% of Indian science graduates, they still only make up about 16% of all physics faculty at universities in India, close to the disappointing global average of roughly 17%. As in many other parts of the world, there are myriad reasons for the low numbers, ranging from social pressure to prioritize families over research careers to a lack of visible role models and even sexual misconduct.

IOP Publishing, which publishes Physics World, recently held a webinar to celebrate the contributions of female physicists in India and explore the challenges they face. It featured Kaveri Hukku, chief executive of ATOS Instruments Marketing Services, Asima Pradhan from SOA University, who recently retired from the Indian Institute of Technology in Kanpur, and Urbasi Sinha from the Raman Research Institute in Bangalore.

Senior leader Shobha Shukla, who organized the IOP Publishing webinar, is one of India’s top researchers in nanophotonics and materials science. (Courtesy: IIT Bombay)

The webinar was organized by Shobha Shukla from the Indian Institute of Technology Bombay in northern Mumbai, who co-chaired the event with Physics World editor-in-chief Matin Durrani. One of India’s leading researchers in nanophotonics and materials science, Shukla is also a member of the editorial board of IOP Publishing’s Journal of Physics: Photonics.

“We are celebrating the women who are writing history in labs, industry and lecture halls right now,” said Shukla in her opening remarks. “This celebration is not a luxury. It is a necessity. It is how we build a culture of equity and innovation.” The following is an edited summary of the webinar, which you can watch in full on the IOP Publishing website.

Expert views

Women with wisdom The three participants on the IOP Publishing webinar were (from left to right) Kaveri Hukku, Asima Pradhan and Urbasi Sinha. (Courtesy: Kaveri Hukku; IIT Kanpur, SOA University; Raman Research Institute)

When asked by Peter Knight – one of the driving forces behind the UK’s quantum-technology programme – what the panel would do if they were science minister, Nicole Gillett said she would seek to make the UK the leader in quantum computing by investing heavily in education. Mehul Malik would cut the costs of scientists moving across borders, pointing out that many big firms have been founded by immigrants. Sarah Alam Malik called for long-term funding – and not to give up if short-term gains don’t transpire. Muhammad Hamza Waseem, meanwhile, said we should invest more in education, research and the international mobility of scientists.

Stayed tuned to Physics World and our international partners throughout the year for more coverage of the IYQ.

Find out more on our quantum channel.

Kaveri Hukku did a bachelor’s and master’s degree in physics before going into industry, where she is now chief executive of the Bangalore‑based firm ATOS Instruments Marketing Services. Founded in 2013, it supplies research institutions and companies in India with advanced scientific instrument and equipment developed by third-party manufacturers from across the world.

Asima Pradhan is a laser physicist whose main interest lies in biomedical optics. With a PhD from City University of New York, Pradhan was based at the Indian Institute of Technology (IIT) in Kanpur for more than 30 years. After formally retiring in 2024, she is now an adjunct professor at SOA University in Bhubaneswar, where she also works for her start-up firm PhotoSpimedix, which is developing portable optical devices for clinical applications.

Urbasi Sinha, who studied physics at Jadavpur University and has both an MSci in natural sciences and a PhD from the University of Cambridge, UK, is head of the quantum information and computing (QuIC) lab at the Raman Research Institute in Bangalore. It is one of the first labs in India to use entangled and “heralded” single-photon sources for quantum science and technology applications – including India’s first project on satellite-based quantum communication.

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How has your career developed and what kind of research are you currently involved in?

Kaveri Hukku: My story is actually very simple. Growing up, I was only interested in sports and games. There was no time for studies in my life. But when adulthood came knocking on my door, my parents sat me down and said “You need to support yourself – you’re not going to do it with your table tennis”.

So with some knowledge in maths and physics, I did a BSc in physics and then a master’s. After that, I found myself at the Indian Institute of Technology Bombay, where I managed to do some physics research at a serious level for a couple of years. But due to many circumstances outside my control, a PhD never happened.

Just as I was trying to decide on a future course for my life, our lab bought an ellipsometer [a device that measures changes in the polarization of light after it interacts with a sample], but the firm who sold us that system couldn’t set it up. It took me a few nights, but I managed to set it up, and from that I also got a job offer with the company. That started my career with instrumentation.

Urbasi Sinha: What excited me about physics from a very early age was how it combined clarity of thought with a sense of wonder, and this is what has driven me throughout my career. I’m an experimental quantum physicist, and I have worked extensively on different aspects, whether it is quantum optics, interferometry, quantum communication, randomness, and so on.

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Essentially, I have used single photons and entangled photons both for making foundational insights and for developing emerging technologies. What is so exciting about my research is that it allows one to ask very deep questions about the nature of quantum mechanics, while also building systems that may have real technological value.

A recurring theme has been to connect fundamental aspects of quantum mechanics with practical questions of trust, validation and performance. A large part of my research currently is focused on quantum communication networks; the challenge of connecting photon sources with quantum memories, entanglement swapping, building these entanglement distribution-based quantum networks as part of India’s national quantum mission.

Basic impact Urbasi Sinha’s research involves asking fundamental quantum questions and then using that knowledge for practical advantage. (Courtesy: iStock/guirong hao)

Asima Pradhan: After completing my master’s degree in physics in India, I moved to the US to do a PhD in experimental biophotonics under the supervision of Robert Alfano at the City University of New York. Coming from a family of doctors and engineers, I’d been keen on working in biophysics and, during my PhD, I did the first fluorescent spectroscopy experiments on human tissue. I’m very proud to have been part of that pioneering work.

When I came back to India and joined IIT Kanpur, I was based in the physics department, where an interdisciplinary research culture simply did not exist
+Asima Pradhan

Then I did a postdoctoral stint at the University of Montreal, Canada, where I conducted some work on photodynamic therapy, collaborating with the physics, chemistry and pathology departments. I had a really good time working in such an interdisciplinary area, but when I came back to India and joined IIT Kanpur, the scenario was very different. I was based in the physics department, where an interdisciplinary research culture simply did not exist back then.

I worked around that and started collaborations with hospitals. We conducted experiments on light-tissue interactions with polarized light. From there, we went into translational research where we actually made a device for use in hospitals. So having begun my professional journey studying particle physics and field theory, I’m now trying to be an entrepreneur. I took voluntary retirement from IIT Kanpur two years ago, but I’m still doing research as an adjunct professor at SOA University in Bhubaneswar.

What skills do you use every day in your role?

Kaveri Hukku: Our profession can be made as simple or as demanding as you want it to be. I try to maintain high technical and analytical skills because the scientists I deal with do a lot of very involved science. But they don’t always come and ask for, say, a specific camera. Instead, they will just tell me what research goal they want to achieve.

So to keep up with them, even on a very simple level, you have to know a little bit of science. You also need to be pragmatic and say if a particular instrument is not right for the experiment, and which devices would be better for their aims. Moreover, it’s a people-facing job, so you have to be able to communicate, and have integrity and honesty such that people feel in safe hands.

Urbasi Sinha: Beyond having a textbook knowledge of physics and maths, precision is very important, as are good human skills. Patience is another vital attribute to have, whether we know it or not, as is the ability to persist when progress is slow. As I’ve grown older, I’ve also realized that communicating research in a way that excites people is vital, because we want to ensure that our field thrives.

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Asima Pradhan: Technical skills, such as precision optical alignment, electronics and Monte Carlo simulations, are essential. But soft skills are vital too. For example, if you want to secure funding, you need to understand the psychology of the people sitting on the other side. The same goes for conducting interdisciplinary research: it can be very difficult to convey things using terminology everybody understands.

What do you like best and least about your job?

Kaveri Hukku: What I like most is keeping in touch with physics and physicists because they still let me potter about their labs and look over the shoulders of their students to make some comment here and there. And I get to work with a lot of young people, which always keeps you young yourself. It’s very satisfying seeing young scientists now building their own labs and wanting to buy instruments from me. That part gives me great joy: in my very small way to be part of their science journey, especially women.

The thing that I really don’t like, and never have, is travelling. My job involves a lot of travelling, packing bags, airports, hotels – but it’s not my cup of tea.

Urbasi Sinha: What I enjoy most is hearing about the everyday problems of younger people in the lab and helping them troubleshoot. I also enjoy translating fundamental quantum mechanics into technology. We do a lot of that sort of work in our in the lab – in fact, we have launched a start-up company called QuSyn Tech, where we are actually building a product.

What I don’t enjoy is avoidable friction. In any academic system, there’s inevitably some friction because research can be challenging. But when there are obstacles that are institutional, administrative or bureaucratic – or when things get petty, especially with our gender – that’s what I don’t enjoy very much.

Asima Pradhan: What I enjoy most is the fact that tissue fluoresces. I always say that when you shine light on someone and if you have the right camera, we all glow. The diffuse scattering itself is, for me, still very exciting. Playing with light and tissue gives me a lot of satisfaction, especially seeing the colours on tissue due to elastic scattering and fluorescence. Now I have a device that I’m testing in hospitals, and so it gives me pure joy just to see that we can get fluorescence from a patient.

What I do not enjoy is the fact that funding is always a little limited. There are restrictions, there are over-regulations, when there should be a certain amount of freedom. Even now, after retirement, I still feel the same.

What difficulties have you faced in your career and how did you overcome those barriers?

Kaveri Hukku: I actually faced huge challenges because, when I started my career, I was pretty much the only woman who was in this field. People would wonder why a woman had come to give this product presentation and she doesn’t even have a pretty face? What is she going to get out of this?

So it was hard getting acceptance, and then there was travelling and the expectation that you would not take time off for family. It was a very warped work–life balance that I had to take on as a challenge back then, because the commercial world was – and is – cut-throat.

If you just keep at it and you believe in yourself, I think you can overcome any gender bias
+Kaveri Hukku

Even now, I can still be the only woman at a meeting, but I just keep going. If you just keep at it and you believe in yourself, I think you can overcome any gender bias.

Powerful force Women make up 40% of all science graduates in India but still face barriers advancing their careers. (Courtesy: Shutterstock/krishnasomya)

Urbasi Sinha: So far as my personal family and extended family is concerned, I have been very privileged. I don’t think I’ve had any barriers in terms of what I wanted to do. But there can be less dramatic barriers, such as being underestimated as a woman or being held to different standards, just because you are a different gender from the rest. It could even be that important decisions are shaped in informal spaces where not everyone may be included.

In the sitcom Friends, there’s this beautiful episode in which Rachel wants to be part of her office culture, but all the decisions are made out on the balcony where everyone is smoking. Rachel doesn’t smoke, but she decides to pick up smoking just to be part of the group. It’s hilarious because it’s a sitcom, but it captures the sentiment very well. Decisions are often taken in surroundings that some of us do not naturally belong to, for whatever reason.

I have definitely encountered challenges of those kinds, the underplayed ones, over the years. What has helped me most has been to stay very anchored in the science, build a very clear intellectual identity, and to remain focused on depth and originality. I also think it’s important to be well prepared, have good documentation and be willing to speak up when needed.

What has helped me most has been to stay anchored in the science, build a clear intellectual identity, and remain focused on depth and originality
+Urbasi Sinha

So I think one develops both resilience and perspective that not every obstacle reflects your worth. That is very important for us to realize as women. And we should not internalize low expectations or limiting assumptions. In the long run, strong work and consistency matter a great deal.

Asima Pradhan: My father was a well-known physicist, which inspired me to study physics. But when I was doing my undergraduate degree 50 years ago, we had a class full of boys and there were only a few girls there. This is true in IIT today; you still see fewer girls.

The boys came from boys’ schools, and had not seen many girls, so they caused some disturbances. Because of this, we had to stand outside, wait for the teacher to come in and then sit in the front, and we hated it. That actually affected us to some extent, but we took it all in our stride. In contrast, during my pre-doctoral studies, we had seven girls and three boys, so that was a privilege – and, interestingly, all of us stayed in physics.

What do you know today, that you wish you knew when you were starting out in your career? And what advice do you have for other women physicists at the start of their career?

Kaveri Hukku: I wish I had known that handling money is extremely important. Whenever money is involved – whether it is in your professional life, with your siblings or with your friends – always keep finances very clear and very well-documented and then you will maintain your relationships well. Money can be like poison, but if you handle it well, you can do a hell of a lot with it. You should neither be scared of it nor give it enough power, but give it the respect it needs and figure out how you want it to be part your life.

Urbasi Sinha: We often talk about working hard, which is very important, but it’s also about what you choose to spend your time on. I have realized, as I have matured, that the choices of problems, collaborators and environment matter just as much as how hard I work.

It’s also important to build depth in your subject and not just say yes to everything. Sometimes we, as women, have a tendency not to say no. Maybe we find it a little more difficult to say no. But if we don’t, then we end up being a Jack of all trades or, in our case, a Jill of all trades, and master of none. That is something I’ve learned as I’ve grown older.

Personal growth Kaveri Hukku thinks women should focus on deepening their knowledge and not be afraid of saying “no”. (Courtesy: iStock/gorodenkoff)

Another thing – and it’s interesting because I didn’t think this in the beginning – is that visibility does matter. The phrase “good work speaks for itself” is something we say, but then at some point it is good to communicate work as well. And Physics World, of course, is the perfect forum for this. Confidence and communication early on as a scientist are important.

My advice to young women physicists would be to invest in real expertise, to cultivate a scientific voice of your own, and not to underestimate your capacity for leadership, because you can seek out mentors, but also those who will really advocate your case.

And finally, sometimes we say: “Only when I’m completely ready, will I step forward”. But you’re never completely ready. So, step forward. Confidence will follow.

Asima Pradhan: When I came back to India from the US, I didn’t realize certain things. For example, I got a job at one place and my husband, who happens to be a physicist too, got a job somewhere else. We were very clear that, once we got back to India, we would somehow be together at some place, but that did not happen. It did not happen due to many reasons that I feel should change.

There are unwritten rules about couples not being in the same department. Some people work around such things, but it did not happen for us. We ended up working for 30 years at two different places, and only now are we together after our retirement. So the younger women need to figure out what their priorities are.

If your priorities are both family and your profession, then do not compromise too much. The next generation loses out by that. So one has to negotiate before committing. The system should also work around it. The times were different when I joined and I see change. However, it is still not enough.

You can rewatch the IOP Publishing webinar on which this article is based at tinyurl.com/2w79m3cs.

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Will this volcano explode, or just ooze? A new mechanism could hold some answers

Isabelle Dumé — Mon, 15 Dec 2025 16:00:53 +0000

Bubbling up: A schematic representation of a volcanic system and a snapshot of one of the team’s experiments. The shear-induced bubbles are marked with red ellipses. (Courtesy: O Roche)

An international team of researchers has discovered a new mechanism that can trigger the formation of bubbles in magma – a major driver of volcanic eruptions. The finding could improve our understanding of volcanic hazards by improving models of magma flow through conduits beneath Earth’s surface.

Volcanic eruptions are thought to occur when magma deep within the Earth’s crust decompresses. This decompression allows volatile chemicals dissolved in the magma to escape in gaseous form, producing bubbles. The more bubbles there are in the viscous magma, the faster it will rise, until eventually it tears itself apart.

“This process can be likened to a bottle of sparkling water containing dissolved volatiles that exolve when the bottle is opened and the pressure is released,” explains Olivier Roche, a member of the volcanology team at the Magmas and Volcanoes Laboratory (LMV) at the Université Clermont Auvergne (UCA) in France and lead author of the study.

Magma shearing forces could induce bubble nucleation

The new work, however, suggests that this explanation is incomplete. In their study, Roche and colleagues at UCA, the French National Research Institute for Sustainable Development (IRD), Brown University in the US and ETH Zurich in Switzerland began with the assumption that the mechanical energy in magma comes from the pressure gradient between the nucleus of a gas bubble and the ambient liquid. “However, mechanical energy may also be provided by shear stress in the magma when it is in motion,” Roche notes. “We therefore hypothesized that magma shearing forces could induce bubble nucleation too.”

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To test their theory, the researchers reproduced the internal movements of magma in liquid polyethylene oxide saturated with carbon dioxide at 80°C. They then set up a device to observe bubble nucleation in situ while the material was experiencing shear stress. They found that the energy provided by viscous shear is large enough to trigger bubble formation – even if decompression isn’t present.

The effect, which the team calls shear-induced bubble nucleation, depends on the magma’s viscosity and on the amount of gas it contains. According to Roche, the presence of this effect could help researchers determine whether an eruption is likely to be explosive or effusive. “Understanding which mechanism is at play is fundamental for hazard assessment,” he says. “If many gas bubbles grow deep in the volcano conduit in a volatile-rich magma, for example, they can combine with each other and form larger bubbles that then open up degassing conduits connected to the surface.

“This process will lead to effusive eruptions, which is counterintuitive (but supported by some earlier observations),” he tells Physics World. “It calls for the development of new conduit flow models to predict eruptive style for given initial conditions (essentially volatile content) in the magma chamber.”

Enhanced predictive power

By integrating this mechanism into future predictive models, the researchers aim to develop tools that anticipate the intensity of eruptions better, allowing scientists and local authorities to improve the way they manage volcanic hazards.

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Looking ahead, they are planning new shear experiments on liquids that contain solid particles, mimicking crystals that form in magma and are believed to facilitate bubble nucleation. In the longer term, they plan to study combinations of shear and compression, though Roche acknowledges that this “will be challenging technically”.

They report their present work in Science.

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+ Physicists find unexpected connection between black hole mergers and thermodynamics + https://physicsworld.com/a/physicists-find-unexpected-connection-between-black-hole-mergers-and-thermodynamics/ + Tue, 04 Aug 2026 13:05:44 +0000 + + + + + https://physicsworld.com/?p=129606 + Properties of a merger remnant can be predicted using a simple entropy-maximization principle

The post Physicists find unexpected connection between black hole mergers and thermodynamics appeared first on Physics World.

Remote work expands collaboration networks but reduces research impact, study suggests

No Author — Mon, 15 Dec 2025 12:41:01 +0000

Deuterium nuclei fired into thin foils of palladium and titanium keep fusing when the nuclei’s incident energies are reduced to the level where the process should be all but extinguished. Instead, physicists in the US have found that as the incident energy is reduced, the fusion rate plateaus – even at the lowest energies probed. Indeed, the low-energy fusion rate exceeds predictions for isolated nuclei by more than 10¹⁸. While significant, the enhanced fusion rates remain far too small for energy generation.

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The results suggest that a metal’s electrons and internal defects can influence how fusion occurs, according to the researchers at the University of California, Davis and Lawrence Berkeley National Laboratory

Nuclear fusion powers the stars, but here on Earth it has so far been impossible to create a practical fusion reactor that delivers usable energy to the electricity grid

“Fusion is hard in the laboratory because positive nuclei repel each other,” explains team member Thomas Schenkel at Berkeley. Quantum mechanics offers a loophole – nuclei can tunnel through the repulsive barrier without having enough kinetic energy to overcome it. However, the tunnelling probability is very small at low energies.

Not fade away

Physicists measure these nuclear collision energies in kiloelectronvolts (keV). Today’s fusion reactors tend to operate plasmas at temperatures that correspond to collision energies of about 10 keV. Below that, reactions fade away, and earlier experiments showed that fusion pretty well stopped near 5 keV.

Yet a solid is a very different environment to a plasma. “Metal lattices contain electrons, defects, and locally concentrated deuterium, all of which can combine to create reaction environments that do not exist in a conventional plasma,” says Jeremy Munday who along with Micah Karahadian is based at UC Davis . The metal’s electron cloud partly shields the repulsion between nuclei, letting them approach more closely. This “screening” effect has been studied since the 1990s and is still not fully understood. The field also carries the scars of the 1989 cold-fusion debacle, during which experiments reporting enhanced fusion rates in solids at room temperature could not be reproduced.

Schenkel and Munday came to this field in the 2010s as participants in a Google-funded effort that revisited the 1989 claims. The programme found no evidence for room-temperature fusion, but it seeded their current collaboration.

Membrane reactor

The team’s apparatus places a metal foil, a quarter of a millimetre thick, between two very different environments. “At the heart of our experimental setup is a type of membrane reactor that combines an electrochemical cell with a deuterium ion beam,” says Schenkel. On one side, an electrochemical process – “similar in principle to charging a battery,” says Munday – pushes deuterium into the metal from a liquid. On the other side, in vacuum, a beam of deuterium ions strikes the same foil, burying itself just a few millionths of a millimetre below the surface.

Each fusion event spits out a fast proton or neutron, caught by two independent detectors. “Detecting these products independently, along with extensive background and control measurements, gave us confidence that the signals came from fusion,” Munday says.

As the team reduced the incident energy, they were surprised. “We observed the well-known exponential rate drop, but then the rates did not drop anymore but rather plateaued as we further decreased the ion energy,” says Schenkel. The plateau appeared below about 2 keV in both metals, and loading extra deuterium electrochemically roughly doubled the yield.

“This is an enormous relative enhancement, although the absolute fusion rate remains far too small for energy production,” Munday stresses. “The immediate significance of our work is therefore the discovery of a new physical regime in which the material actively influences the nuclear reaction, rather than the demonstration of a practical energy source.”

Welcome corroboration

Konrad Czerski, professor of nuclear and medical physics at the University of Szczecin, Poland, sees the result as welcome corroboration. “The Berkeley study represents an independent confirmation of the effect found by our research group over two years ago within Europe’s CleanHME project,” he says. His team saw a similar plateau in zirconium, palladium and titanium with a different technique. The palladium results of the two groups agree well, he notes, but the titanium data differ.

Czerski is not persuaded by the American team’s explanation, which attributes the plateau to unusually strong screening in the foil’s damaged surface layer. His group’s measurements, he argues, “demonstrate unambiguously that the yield plateau arises from fusion of deuterium at ordinary thermal energies, and the screening energy doesn’t change.”

The disagreement underlines how much remains open in the field. “The most important next step is to identify the microscopic origin of the low-energy plateau,” says Munday. This would involve untangling the roles of screening, surface damage and the way deuterium moves and gets trapped in the metal. The US team also wants to test whether light or crystal vibrations can affect the reaction rate. Near-term applications, he suggests, might include compact neutron sources rather than reactors.

Czerski has a bolder vision for the future. “The experimental setups and the results obtained can launch a new research field focused on materials and enhancing the electron screening effect in nuclear reactions,” he says – one that “can finally lead to commercial applications, and even possibly to construction of a new energy source.”

The research is described in Nature Communications.

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Portable breast ultrasound enables imaging between cancer screening exams

Cynthia E Keen — Mon, 03 Aug 2026 09:00:16 +0000

In vivo ultrasound images From left to right: a cyst, breast implant, dense fibrous tissue and solid mass. The top row shows conventional 2D ultrasound images while the bottom row shows the corresponding images using the 3D PURE system. (Courtesy: the researchers)

Women at high risk of breast cancer are more susceptible to developing cancers in the gap between routine screening exams. These so-called “interval cancers” tend to be fast-growing and account for 20% to 30% of all breast cancer cases.

To identify aggressive cancers that develop between scheduled screenings, researchers at Massachusetts Institute of Technology (MIT) have developed a point-of-care ultrasound system that generates high-resolution 3D images of breast tissue. The 3D portable ultrasound system for real-time examination (3D PURE) supplements mammography with its ability to detect anomalies reliably in dense breast tissue (in which mammography is less sensitive).

Guided by an easy-to-use visual interface, 3D PURE enables a nurse, a physician such as a primary care provider or gynaecologist, or even the patient herself to frequently perform longitudinal breast imaging.

Second-generation design

Principal investigator Canan Dagdeviren explains that this second-generation prototype overcomes limitations of a prior system designed by the MIT team, through advances in transducer design, acoustic materials and adaptive beamforming. These developments have enabled real-time wide-angle 3D imaging in a portable form factor, with improved image resolution to accurately identify cysts, solid masses, fibroadenomas and microcalcifications.

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The ultrasound system comprises a newly designed 128-element box-shaped 2D transducer array incorporating a corner-gap offset geometry, which suppresses peak crosstalk by 3.73 dB at the corner-most element. This design prevents amplifier saturation, and supports operational transmit voltages of up to 24 V. The array is integrated into a compact multilayer electronics stack comprising preamplifiers, transmit electronics and a custom chirp data acquisition system.

There’s also a conductive backing layer (a toluene-diluted polyurethane matrix with a high percentage of tungsten and zirconia filler) that forms a continuous shielding layer around the elements, improving acoustic attenuation and providing electromagnetic shielding. The compliant mechanical nature of the material enhances acoustic damping, reducing ultrasound reverberations more effectively and improving signal fidelity.

“The addition of a backing layer to the ultrasound transducer is a key advantage to the system,” explains co-lead author Md Osman Goni Nayeem. “It provides both better directionality of ultrasound waves and better bandwidth, which improves the resolution and quality of the resulting images.”

The researchers also incorporated layered aberration-correction reconstruction (LACR), an adaptive 3D beamformer, into the 3D PURE design. LACR compensates for the heterogeneous speed-of-sound in the breast, which comprises glandular and fibrous tissues plus a superficial layer of fat. They believe that this represents the first wide-angle 3D ultrasound imaging system to implement aberration-correction beamforming.

“What we are trying to do is predict the speed-of-sound properties of the tissue being imaged, and then use that to reconstruct the image more accurately. We see up to a 10% improvement for the resolution just by applying this [beamforming] technique,” says co-lead author Shrihari Viswanath in a press statement.

Experimental validation The 3D ultrasound probe is positioned on a tissue-mimicking breast phantom for visualization of embedded microtargets. (Courtesy: the researchers)

The system is designed for ease of use. A visual user interface called “Mirror my First UltraSound” (MyFUS) guides users to reliably reposition the ultrasound probe at the same anatomical location during repeated imaging and long-term monitoring. Meanwhile, a wide field-of-view minimizes the number of scans needed to cover the entire breast.

The team undertook an in vitro study comparing the performance of the 3D PURE system with that of a conventional 2D handheld ultrasound system (HHUS). Ten study participants imaged a breast-shaped tissue phantom embedded with sub-millimetre targets. Nine of the 10 participants showed improved microtarget detection efficiency with 3D PURE relative to the conventional system – identifying more of the targets using 3D PURE (79.7%, compared with 60.7% for the 2D HHUS), with a higher detection efficiency (14.02% of available targets per minute, compared with 9.58%).

The researchers also worked with radiologists to assess a variety of breast anomalies in vivo. The radiologists verified that the 3D PURE system could accurately visualize calcifications, cysts, implants, fibrous tissues and solid masses within a large volumetric field-of-view. The researchers independently validated the system’s accuracy when imaging dense fibrous breast tissue and rib structures.

Seven volunteers with no prior experience of using an ultrasound system tested the MyFUS visual interface. After initial instruction by an ultrasound technician, they were able to repetitively position the probe at a specific location on their breasts, achieving a 94.10% mean overlap value on frontal projections, and 87.42% on side projections. This test reconfirmed that novice users could achieve reproducible longitudinal monitoring results with the aid of the visual interface.

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The researchers now hope to create an interface for use with mobile phones or tablets. This type of system could make breast ultrasound more accessible to patients in economically constrained countries lacking adequate breast cancer scanning and regions with shortages of trained ultrasound technicians.

“The high operator dependence of conventional ultrasound is a barrier to its use in decentralized or home-monitoring settings,” the researchers write. “The MyFUS vision interface transforms longitudinal monitoring from an expert-driven procedure to a self-guided, reproducible process that can be used by novice users. This reproducibility is vital for longitudinal monitoring in limited clinical settings, to regularly track the growth of an anomaly or the response of a tumour to therapies without visiting clinics.”

The 3D PURE system is described in Nature Communications.

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How well do you know AI? Try our interactive quiz to find out

No Author — Mon, 15 Dec 2025 12:00:02 +0000

There are 12 questions in total: blue is your current question and white means unanswered, with green and red being right and wrong. Check your scores at the end – and why not test your colleagues too?

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How did you do?

10–12 Top shot – congratulations, you’re the next John Hopfield

7–9 Strong skills – good, but not quite Nobel standard

4–6 Weak performance – should have asked ChatGPT

0–3 Worse than random – are you a bot?

Physics World‘s coverage of this interactive quiz is supported by Reports on Progress in Physics, which offers unparalleled visibility for your ground-breaking research.

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International Year of Quantum Science and Technology quiz

Matin Durrani — Mon, 15 Dec 2025 10:00:08 +0000

This quiz was first published in February 2025. Now you can enjoy it in our new interactive quiz format and check your final score. There are 18 questions in total: blue is your current question and white means unanswered, with green and red being right and wrong.

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Peeing at the Grand Prix just got a lot more meaningful. In the latest episode of Physics World Stories, Lucy Bell-Reeves and Olivia Wilson, who work for the start-up NPK Recovery, based at the University of the West of England, explain how their mobile system upcycles urine into fertilizer, right where it’s produced.

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The pair unpack the physics and chemistry behind their approach, contrasting it with the energy-intensive Haber-Bosch process, which converts natural gas into ammonia under extreme heat and pressure at centralized plants. With the UK importing 100% of its nitrogen, and recent global conflicts exposing the fragility of fertilizer supply chains, the case for local, circular alternatives is growing stronger.

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The post International Year of Quantum Science and Technology quiz appeared first on Physics World.

Host Andrew Glester hears about the pair’s experience at the British Grand Prix in Silverstone, the UK’s leg of the Formula 1 World Championship. Bell-Reeves and Wilson reflect on what it’s like to experience the “Grand Pee”, and how attendees react when they discover where their urine ends up.

While not pitched as a replacement for industrial-scale ammonia production, the system offers a smart fix for off-grid sites facing sudden spikes in human waste.

The post From pit stop to plant food: how Grand Prix crowd’s urine becomes fertilizer appeared first on Physics World.

Components of RNA among life’s building blocks found in NASA asteroid sample

No Author — Fri, 12 Dec 2025 11:30:01 +0000

More molecules and compounds vital to the origin of life have been detected in asteroid samples delivered to Earth by NASA’s OSIRIS-REx mission. The discovery strengthens the case that not only did life’s building blocks originate in space, but that the ingredients of RNA, and perhaps RNA itself, were brought to our planet by asteroids.

Two new papers in Nature Geoscience and Nature Astronomy describe the discovery of the sugars ribose and glucose in the 120 g of samples returned from the near-Earth asteroid 101955 Bennu, as well as an unusual carbonaceous “gum” that holds important compounds for life. The findings complement the earlier discovery of amino acids and the nucleobases of RNA and DNA in the Bennu samples.

A third new paper, in Nature Astronomy, addresses the abundance of pre-solar grains, which is dust that originated from before the birth of our Solar System, such as dust from supernovae. Scientists led by Ann Nguyen of NASA’s Johnson Space Center found six times more dust direct from supernova explosions than is found, on average, in meteorites and other sampled asteroids. This could suggest differences in the concentration of different pre-solar dust grains in the disc of gas and dust that formed the Solar System.

Space gum

It’s the discovery of organic materials useful for life that steals the headlines, though. For example, the discovery of the space gum, which is essentially a hodgepodge chain of polymers, represents something never found in space before.

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Scott Sandford of NASA’s Ames Research Center, co-lead author of the Nature Astronomy paper describing the gum discovery, tells Physics World: “The material we see in our samples is a bit of a molecular jumble. It’s carbonaceous, but much richer in nitrogen and, to a lesser extent, oxygen, than most of the organic compounds found in extraterrestrial materials.”

Sandford refers to the material as gum because of its pliability, bending and dimpling when pressure is applied, rather like chewing gum. And while much of its chemical functionality is replicated in similar materials on our planet, “I doubt it matches exactly with anything seen on Earth,” he says.

Initially, Sandford found the gum using an infrared microscope, nicknaming the dust grains containing the gum “Lasagna” and “Neapolitan” because the grains are layered. To extract them from the rock in the sample, Sandford went to Zack Gainsforth of the University of California, Berkeley, who specializes in analysing and extracting materials from samples like this.

Platinum scaffolding

Having welded a tungsten needle to the Neapolitan sample in order to lift it, the pair quickly realised that the grain was very delicate.

“When we tried to lift the sample it began to deform,” Gainsforth says. “Scott and I practically jumped out of our chairs and brainstormed what to do. After some discussion, we decided that we should add straps to give it enough mechanical rigidity to survive the lift.”

Fragile sample A microscopic particle of asteroid Bennu is manipulated under a transmission electron microscope. To move the 30 µm fragment for further analysis, the researchers reinforced it with thin platinum strips (the L shape on the surface). (Courtesy: NASA/University of California, Berkeley)

By straps, Gainsforth is referring to micro-scale platinum scaffolding applied to the grain to reinforce its structure while they cut it away with an ion beam. Platinum is often used as a radiation shield to protect samples from an ion beam, “but how we used it was anything but standard,” says Gainsforth. “Scott and I made an on-the-fly decision to reinforce the samples based on how they were reacting to our machinations.”

With the sample extracted and reinforced, they used the ion beam cutter to shave it down until it was a thousand times thinner than a human hair, at which point it could be studied by electron microscopy and X-ray spectrometry. “It was a joy to watch Zack ‘micro-manipulate’ [the sample],” says Sandford.

The nitrogen in the gum was found to be in nitrogen heterocycles, which are the building blocks of nucleobases in DNA and RNA. This brings us to the other new discovery, reported in Nature Geoscience, of the sugars ribose and glucose in the Bennu samples, by a team led by Yoshihiro Furukawa of Tohoku University in Japan.

The ingredients of RNA

Glucose is the primary source of energy for life, while ribose is a key component of the sugar-phosphate backbone that connects the information-carrying nucleobases in RNA molecules. Furthermore, the discovery of ribose now means that everything required to assemble RNA molecules is present in the Bennu sample.

Notable by its absence, however, was deoxyribose, which is ribose minus one oxygen atom. Deoxyribose in DNA performs the same job as ribose in RNA, and Furukawa believes that its absence supports a popular hypothesis about the origin of life on Earth called RNA world. This describes how the first life could have used RNA instead of DNA to carry genetic information, catalyse biochemical reactions and self-replicate.

Intriguingly, the presence of all RNA’s ingredients on Bennu raises the possibility that RNA could have formed in space before being brought to Earth.

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“Formation of RNA from its building blocks requires a dehydration reaction, which we can expect to have occurred both in ancient Bennu and on primordial Earth,” Furukawa tells Physics World.

However, RNA would be very hard to detect because of its expected low abundance in the samples, making identifying it very difficult. So until there’s information to the contrary, “the present finding means that the ingredients of RNA were delivered from space to the Earth,” says Furukawa.

Nevertheless, these discoveries are major milestones in the quest of astrobiologists and space chemists to understand the origin of life on Earth. Thanks to Bennu and the asteroid 162173 Ryugu, from which a sample was returned by the Japanese Aerospace Exploration Agency (JAXA) mission Hayabusa2, scientists are increasingly confident that the building blocks of life on Earth came from space.

The post Components of RNA among life’s building blocks found in NASA asteroid sample appeared first on Physics World.

+ AI sniffs out tuberculosis in breath’s chemical signature + https://physicsworld.com/a/ai-sniffs-out-tuberculosis-in-breaths-chemical-signature/ + Fri, 31 Jul 2026 11:00:35 +0000 + + + + + https://physicsworld.com/?p=129547 + Machine learning decodes the complex chemical signatures in human breath to deliver rapid, non-invasive tuberculosis diagnoses

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Institute of Physics celebrates 2025 Business Award winners at parliamentary event

Michael Banks — Fri, 12 Dec 2025 11:00:26 +0000

A total of 14 physics-based firms in sectors from quantum and energy to healthcare and aerospace have won 2025 Business Awards from the Institute of Physics (IOP), which publishes Physics World. The awards were presented at a reception in the Palace of Westminster yesterday attended by senior parliamentarians and policymakers as well as investors, funders and industry leaders.

The IOP Business Awards, which have been running since 2012, recognise the role that physics and physicists play in the economy, creating jobs and growth “by powering innovation to meet the challenges facing us today, ranging from climate change to better healthcare and food production”. More than 100 firms have now won Business Awards, with around 90% of those companies still commercially active.

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The parliamentary event honouring the 2025 winners were hosted by Dave Robertson, the Labour MP for Lichfield, who spent 10 years as a physics teacher in Birmingham before working for teaching unions. There was also a speech from Baron Sharma, who studied applied physics before moving into finance and later becoming a Conservative MP, Cabinet minister and president of the COP-26 climate summit.

Seven firms were awarded 2025 IOP Business Innovation Awards, which recognize companies that have “delivered significant economic and/or societal impact through the application of physics”. They include Oxford-based Tokamak Energy, which has developed “compact, powerful, robust, quench-resilient” high-temperature superconducting magnets for commercial fusion energy and for propulsion systems, accelerators and scientific instruments.

(courtesy: Carmen Valino)

Oxford Instruments was honoured for developing a novel analytical technique for scanning electron microscopes, enabling new capabilities and accelerating time to results by at least an order of magnitude. Ionoptika, meanwhile, was recognized for developing Q-One, which is a new generation of focused ion-beam instrumentation, providing single atom through to high-dose nanoscale advanced materials engineering for photonic and quantum technologies.

The other four winners were: electronics firm FlexEnable for their organic transistor materials; Lynkeos Technology for the development of muonography in the nuclear industry; the renewable energy company Sunamp for their thermal storage system; and the defence and security giant Thales UK for the development of a solid-state laser for laser rangefinders.

Business potential

Six other companies have won an IOP Start-up Award, which celebrates young companies “with a great business idea founded on a physics invention, with the potential for business growth and significant societal impact”. They include Astron Systems for developing “long-lifetime turbomachinery to enable multi-reuse small rocket engines and bring about fully reusable small launch vehicles”, along with MirZyme Therapeutics for “pioneering diagnostics and therapeutics to eliminate preeclampsia and transform maternal health”.

The other four winners were: Celtic Terahertz Technology for a metamaterial filter technology; Nellie Technologies for a algae-based carbon removal technology; Quantum Science for their development of short-wave infrared quantum dot technology; and Wayland Additive for the development and commercialisation of charge-neutralised electron beam metal additive manufacturing.

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James McKenzie, a former vice-president for business at the IOP, who was involved in judging the awards, says that all awardees are “worthy winners”. “It’s the passion, skill and enthusiasm that always impresses me,” McKenzie told Physics World.

iFAST Diagnostics were also awarded the IOP Lee Lucas Award that recognises early-stage companies taking innovative products into the medical and healthcare sector. The firm, which was spun out of the University of Southampton, develops blood tests that can test the treatment of bacterial infections in a matter of hours rather than days. They are expecting to have approval for testing next year.

“Especially inspiring was the team behind iFAST,” adds McKenzie, “who developed a method to test very rapid tests cutting time from 48 hours to three hours, so patients can be given the right antibiotics.”

“The award-winning businesses are all outstanding examples of what can be achieved when we build upon the strengths we have, and drive innovation off the back of our world-leading discovery science,” noted Tom Grinyer, IOP chief executive officer. “In the coming years, physics will continue to shape our lives, and we have some great strengths to build upon here in the UK, not only in specific sectors such as quantum, semiconductors and the green economy, but in our strong academic research and innovation base, our growing pipeline of spin-out and early-stage companies, our international collaborations and our growing venture capital community.”

For the full list of winners, see here.

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+ Heat-transfer fins give phase change materials a boost + https://physicsworld.com/a/heat-transfer-fins-give-phase-change-materials-a-boost/ + Fri, 31 Jul 2026 08:00:50 +0000 + + + + + + https://physicsworld.com/?p=129542 + Modelling points the way towards optimal designs for systems that store and release heat

The post Heat-transfer fins give phase change materials a boost appeared first on Physics World.

Leftover gamma rays produce medically important radioisotopes

Isabelle Dumé — Fri, 12 Dec 2025 09:00:46 +0000

Pressure-dependent degradation mechanisms Low stack pressure accelerates cathode cracking, while high pressure promotes lithium plating. At the optimal pressure, balanced interparticle contact and porosity minimize mechanical degradation. (Courtesy: CC BY 4.0/Nat Energy 10.1038/s41560-026-02087-6)

Engineers are constantly striving to improve the safety and performance of electric vehicle (EV) batteries. Much effort has been put into developing new electrode materials over the years, but future improvements may not follow the same path and may just be as simple as utilizing physical pressure.

A recent study, led by researchers at the University of Cambridge, suggests that EV batteries could be made to last up to twice as long, by applying the right amount of pressure to the electrodes. It is, however, a fine balancing act, as too high or too low a pressure can cause the battery to fail. To employ this approach in real world systems, engineers will need to make sure that the process is easily repeatable without significant pressure error, but it’s an interesting avenue of battery engineering that has come to fruition.

“We carried this work out to improve the sustainability of batteries,” says Michael de Volder, one of the lead researchers on the study. “Given that we are not very good at recycling batteries, extending the lifetime of batteries reduces the need for mining critical minerals for making new batteries and therefore improves their sustainability.”

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For their study, reported in Nature Energy, the researchers developed a dilatometer with pneumatic bellows to apply pressure to the electrodes. The bellows act like a clamp to maintain a uniform and constant pressure on the electrode, while a sensor detects small volume changes that occur as the battery charges and discharges.

The researchers tested their electrode pressurization approach on commercial nickel manganese cobalt (NMC) lithium-ion pouch batteries (which have a flexible packaging), without changing their electrolyte or electrode composition. By using commercial batteries with a standard setup, they could test them fairly under different pressures.

“In this work we optimized how hard battery anodes and cathodes should be pushed together to maximize the lifetime of batteries,” de Volder tells Physics World. “Importantly, we also unravel which degradation mechanisms kick in if you press too hard, or not hard enough.”

Doubling battery lifetime

The researchers found that increasing the stack pressure fourfold over typical initial values used in conventional coin cells – to an optimal pressure of 12.5 bar – doubled the lifetime of the NMC811 cells. They compared the results with NMC cells tested at an extra-low pressure of 1.5 bar, a low pressure of 3 bar, a medium pressure of 6.5 bar and a high pressure of 37.5 bar.

Different degradation mechanisms emerged at high and low pressures outside of the optimal pressure zone. Low stack pressure accelerated cathode cracking, causing an increase in transition metal dissolution and excessive formation of the solid electrolyte interphase (SEI) layer. The cracking is likely due to a small number of particles bearing most of the mechanical load, leading to localized high-stress concentrations that initiate crack propagation.

Higher stack pressures, meanwhile, caused increased lithium plating on the anode. The team observed that the electrode thickness reduced during initial cycling but then underwent rapid thickness growth. When the electrodes are at their thinnest, they have a lower porosity that limits lithium transport, leading to higher overpotentials and higher lithium plating. This increases the amount of “dead” lithium and reduces the usable lithium inventory in the battery, causing it to degrade faster.

“We found that when the pressure applied to battery cells is sub-optimal, certain dangerous degradation processes can be accelerated. So, in a way, pressure optimization might improve the safety of batteries. However, more research is needed before we can draw reliable conclusions on this front,” says de Volder.

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The pressurization results in this study are still in the early stages, but if shown to be viable at scale in commercial systems, could help EV batteries to last longer. In theory, this could give second-hand EVs a higher market value as the vehicle will have a longer battery life when sold. Additionally, if EV batteries can last longer, it will reduce the pressure on lithium mining operations and reduce the amount of raw material required for battery manufacturing (assuming the same demand) – something that is becoming an issue due to the skyrocketing price of lithium.

Cambridge Enterprise, the university’s innovation arm, has filed a patent, so the research team and university obviously see commercial viability in the process. When asked about the team’s future plans, de Volder tells Physics World that “we studied pressure optimization for one specific battery chemistry, but we anticipate that gains can be made in the lifetime of other battery chemistries too”.

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Top 10 Breakthroughs of the Year in physics for 2025 revealed

Hamish Johnston — Thu, 11 Dec 2025 14:27:27 +0000

Physics World is delighted to announce its Top 10 Breakthroughs of the Year for 2025, which includes research in astronomy, antimatter, atomic and molecular physics and more. The Top Ten is the shortlist for the Physics World Breakthrough of the Year, which will be revealed on Thursday 18 December.

Our editorial team has looked back at all the scientific discoveries we have reported on since 1 January and has picked 10 that we think are the most important. In addition to being reported in Physics World in 2025, the breakthroughs must meet the following criteria:

Significant advance in knowledge or understanding

Importance of work for scientific progress and/or development of real-world applications

Of general interest to Physics World readers

Here, then, are the Physics World Top 10 Breakthroughs for 2025, listed in no particular order. You can listen to Physics World editors make the case for each of our nominees in the Physics World Weekly podcast. And, come back next week to discover who has bagged the 2025 Breakthrough of the Year.

Finding the stuff of life on an asteroid

The first superfluid molecule

Hollow-core fibres break 40-year limit on light transmission

First patient treatments delivered with proton arc therapy

PAT pioneers The research team in the proton therapy gantry room. (Courtesy: UO Fisica Sanitaria and UO Protonterapia, APSS, Trento)

A protein qubit for quantum biosensing

First two-dimensional sheets of metal

To Guangyu Zhang, Luojun Du and colleagues at the Institute of Physics of the Chinese Academy of Sciences for producing the first 2D sheets of metal. Since the discovery of graphene – a sheet of carbon just one atom thick – in 2004, hundreds of other 2D materials have been fabricated and studied. In most of these, layers of covalently bonded atoms are separated by gaps where neighbouring layers are held together only by weak van der Waals (vdW) interactions, making it relatively easy to “shave off” single layers to make 2D sheets. Many thought that making atomically thin metals, however, would be impossible given that each atom in a metal is strongly bonded to surrounding atoms in all directions. The technique developed by Zhang and Du and colleagues involves heating powders of pure metals between two monolayer-MoS₂/sapphire vdW anvils. Once the metal powders are melted into a droplet, the researchers applied a pressure of 200 MPa and continued this “vdW squeezing” until the opposite sides of the anvils cooled to room temperature and 2D sheets of metal were formed. The team produced five atomically thin 2D metals – bismuth, tin, lead, indium and gallium – with the thinnest being around 6.3 Å. The researchers say their work is just the “tip of the iceberg” and now aim to study fundamental physics with the new materials.

Quantum control of individual antiprotons

Exquisite control Physicist Barbara Latacz at the BASE experiment at CERN. (Courtesy: CERN)

A smartphone-based early warning system for earthquakes

A “weather map” for a gas giant exoplanet

Highest-resolution images ever taken of a single atom

Physics World‘s coverage of the Breakthrough of the Year is supported by Reports on Progress in Physics, which offers unparalleled visibility for your ground-breaking research.

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Exploring this year’s best physics research in our Top 10 Breakthroughs of 2025

Hamish Johnston — Thu, 11 Dec 2025 14:27:25 +0000

This episode of the Physics World Weekly podcast features a lively discussion about our Top 10 Breakthroughs of 2025, which include important research in quantum sensing, planetary science, medical physics, 2D materials and more. Physics World editors explain why we have made our selections and look at the broader implications of this impressive body of research.

The top 10 serves as the shortlist for the Physics World Breakthrough of the Year award, the winner of which will be announced on 18 December.

Links to all the nominees, more about their research and the selection criteria can be found here.

Physics World‘s coverage of the Breakthrough of the Year is supported by Reports on Progress in Physics, which offers unparalleled visibility for your ground-breaking research.

The post Exploring this year’s best physics research in our Top 10 Breakthroughs of 2025 appeared first on Physics World.

This episode of the Physics World Weekly podcast features Antonia Seymour, who is chief executive of IOP Publishing.

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Seymour has more than 30 years’ experience in a publishing industry that has evolved significantly from the days of paper journals to today’s sophisticated digital technologies.

In this interview we explore how scholarly publishers are responding to the rapid growth in research output, the rise of artificial intelligence and the increase in threats to research integrity.

A wholly owned subsidiary of the Institute of Physics, IOP Publishing produces more than 100 scholarly journals as well as Physics World.

The post How scholarly publishers are safeguarding trust in science appeared first on Physics World.

Astronomers observe a coronal mass ejection from a distant star

Isabelle Dumé — Thu, 11 Dec 2025 09:00:30 +0000

The Sun regularly produces energetic outbursts of electromagnetic radiation called solar flares. When these flares are accompanied by flows of plasma, they are known as coronal mass ejections (CMEs). Now, astronomers at the Netherlands Institute for Radio Astronomy (ASTRON) have spotted a similar event occurring on a star other than our Sun – the first unambiguous detection of a CME outside our solar system.

Astronomers have long predicted that the radio emissions associated with CMEs from other stars should be detectable. However, Joseph Callingham, who led the ASTRON study, says that he and his colleagues needed the highly sensitive low-frequency radio telescope LOFAR – plus ESA’s XMM-Newton space observatory and “some smart software” developed by Cyril Tasse and Philippe Zarka at the Observatoire de Paris-PSL, France – to find one.

A short, intense radio signal from StKM 1-1262

Using these tools, the team detected short, intense radio signals from a star located around 40 light-years away from Earth. This star, called StKM 1-1262, is very different from our Sun. At only around half of the Sun’s mass, it is classed as an M-dwarf star. It also rotates 20 times faster and boasts a magnetic field 300 times stronger. Nevertheless, the burst it produced had the same frequency, time and polarization properties as the plasma emission from an event called a solar type II burst that astronomers identify as a fast CME when it comes from the Sun.

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“This work opens up a new observational frontier for studying and understanding eruptions and space weather around other stars,” says Henrik Eklund, an ESA research fellow working at the European Space Research and Technology Centre (ESTEC) in Noordwijk, Netherlands, who was not involved in the study. “We’re no longer limited to extrapolating our understanding of the Sun’s CMEs to other stars.”

Implications for life on exoplanets

The high speed of this burst – around 2400 km/s – would be atypical for our own Sun, with only around 1 in every 20 solar CMEs reaching that level. However, the ASTRON team says that M-dwarfs like StKM 1-1262 could emit CMEs of this type as often as once a day.

Spotting a distant coronal mass ejection: An artist’s impression of XMM-Newton. (Courtesy: ESA/C Carreau)

According to Eklund, this has implications for extraterrestrial life, as most of the known planets in the Milky Way are thought to orbit stars of this type, and such bursts could be powerful enough to strip their atmospheres. “It seems that intense space weather may be even more extreme around smaller stars – the primary hosts of potentially habitable exoplanets,” he says. “This has important implications for how these planets keep hold of their atmospheres and possibly remain habitable over time.”

Erik Kuulkers, a project scientist at XMM-Newton who was also not directly involved in the study, suggests that this atmosphere-stripping ability could modify the way we hunt for life in stellar systems akin to our Solar System. “A planet’s habitability for life as we know it is defined by its distance from its parent star – whether or not it sits within the star’s ‘habitable zone’, a region where liquid water can exist on the surface of planets with suitable atmospheres,” Kuulkers says. “What if that star was especially active, regularly producing CMEs, however? A planet regularly bombarded by these ejections might lose its atmosphere entirely, leaving behind a barren uninhabitable world, despite its orbit being ‘just right’.

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Kuulkers adds that the study’s results also contain lessons for our own Solar System. “Why is there still life on Earth despite the violent material being thrown at us?” he asks. “It is because we are safeguarded by our atmosphere.”

Seeking more data

The ASTRON team’s next step will be to look for more stars like StKM 1-1262, which Kuulkers agrees is a good idea. “The more events we can find, the more we learn about CMEs and their impact on a star’s environment,” he says. Additional observations at other wavelengths “would help”, he adds, “but we have to admit that events like the strong one reported on in this work don’t happen too often, so we also need to be lucky enough to be looking at the right star at the right time.”

For now, the ASTRON researchers, who report their work in Nature, say they have reached the limit of what they can detect with LOFAR. “The next step is to use the next generation Square Kilometre Array, which will let us find many more such stars since it is so much more sensitive,” Callingham tells Physics World.

The post Astronomers observe a coronal mass ejection from a distant star appeared first on Physics World.

+ Identifying maximum viscosity: a slide puzzle + https://physicsworld.com/a/identifying-maximum-viscosity-a-slide-puzzle/ + Thu, 30 Jul 2026 12:30:47 +0000 + + + + https://physicsworld.com/?p=129537 + Can you reconstruct an image of part of the Mid-Atlantic Ridge in this interactive slide puzzle?

The post Identifying maximum viscosity: a slide puzzle appeared first on Physics World.

Sterile neutrinos: KATRIN and MicroBooNE come up empty handed

Hamish Johnston — Wed, 10 Dec 2025 16:49:58 +0000

Physicists in the UK have reacted with dismay following the decision by the Science and Technology Facilities Council (STFC) to cancel funding for several high-profile international projects. The Institute of Physics (IOP), which publishes Physics World, says that the axing of support threatens the UK’s international reputation as well as the ability to attract people into the subject.

The STFC cuts come after the council announced late last year that its core annual budget would rise by only £7m to £842m over the four years from 2026 to 2030. One of seven research councils within UK Research and Innovation (UKRI), the STFC runs the UK’s national facilities and supports particle physics, astronomy and nuclear physics (PPAN) research in the UK.

In a strongly worded statement, IOP president Paul Howarth is now urging the government to review “this ruinous set of decisions”, calling the cuts a “terrible blow” that will do “real damage” to the UK’s scientific reputation and put future economic growth at risk.

“Despite reassurances, physics has not been protected, crucial facilities remain under threat and jobs are being lost,” says Howarth. “Scientific capability that has taken years to build up is being put at risk by these decisions – it undermines a number of our most important international collaborations and could put a whole generation of young people off a career in science.”

Balancing the books

Although UKRI has received a record £39bn investment across the four-year period, it said last year that projects at STFC would need to be cut given inflation, rising energy costs as well as “unfavourable movements in foreign exchange rates”. Together, the STFC’s annual costs are projected to rise to over £1bn per year by 2030, forcing it to find ways to balance its books by 2029.

Earlier this year, the STFC said it would have to cut its core science budget by at least 30% over 2024/2025 levels. UKRI also noted it would stop funding two UK facilities – the Relativistic Ultrafast Electron Diffraction and Imaging facility and the C-MASS mass spectrometry centre. A UK-led upgrade to the LHCb experiment at CERN and support for the Electron–Ion Collider at Brookhaven in the US would be axed too.

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That announcement caused significant distress within the physics community, prompting the heads of UK university physics departments to publish an open letter to then science minister Patrick Vallance, expressing their “deep concern” about funding changes adding that such cuts cause “reputational risk”.

UKRI then carried out further consultation with researchers and the STFC’s expert advisory bodies, with the results of this “funding prioritisation exercise”now revealed. There is some good news for STFC-funded “discovery-led” PPAN research, which physicists had feared could be cut by a third. Following lobbying, UKRI says this work is being “protected”, although it will still fall by 2.7% over the next four years.

Under attack

While facilities such as Diamond Light Source, the ISIS Neutron and Muon Source, and the Central Laser Facility will not be mothballed, the STFC’s budget for multidisciplinary facilities will reduce by 15% over the next four years to save £28m. As a result, ISIS will have to reduce operational time at the facility.

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Yet the STFC warns that if saving and income targets for the programme are not met by 2028 then further action could be taken, which could involve closing a multidisciplinary facility.

STFC’s national laboratories and estates budget fares slightly better, falling by 8% over the four-year period, but individual facilities will be hit harder. The operational budget of the Boulby Underground Mine, for example, will be slashed by 40%.

Particle fever

The STFC insists that subscriptions for international projects, such as CERN and the European Southern Observatory, will remain protected despite their costs expecting to rise by 19% over the next four years. But other projects, including the EIC as well as the LHCb upgrade, will not be funded. The latter is expected to operate until 2033 by which time it would have reached the end of its lifetime after years of intense radiation damage.

An upgrade was planned so that it could take advantage of the upgrade to the LHC – the High-Luminosity LHC (HL-LHC) – and offer an order of magnitude increase in luminosity over upgrade I.

Down and out? UK funding for a major upgrade to LHCb has been cancelled increasing the possibility that it won’t go ahead. (Courtesy: CERN)

Tim Gershon from the University of Warwick, who became international spokesperson for the collaboration this month, says that the outlook for STFC-funded science is “grim”.

“With a 15% cut last year and an outlook that sees funding shrink further due to inflationary pressure, not even excellent-rated and internationally-leading science like LHCb can be supported,” he adds. “LHCb is the canary in the coalmine for the future sustainability of particle physics and astronomy research.”

Gershon states that the decision to cut UK involvement in LHCb will throw away the leadership it has built up. “Not only is this a tragedy for researchers and engineers who have dedicated their lives to making LHCb one of the most successful experiments in history, it destroys opportunities for current and future students to be involved in world-leading scientific discovery,” he adds.

This is a short-sighted move, to save a tiny fraction of the overall UK science budget
+Catherine Haymans

Gershon says it will take some time to understand what the UK’s decision means for the upgrade and how other funding agencies will react but without UK expertise it will be hard to progress given the UK is the largest partner in LHCb with a 20% stake.

“Ultimately, the LHCb Upgrade is an essential part of the full exploitation of the HL-LHC, which is the top priority of the European and CERN strategies for particle physics,” adds Gershon. “We are determined to deliver the best detector that is possible within the available resources. But such a major change to the level of expected resources makes this extremely difficult.”

Peter Millington, a particle physicist from the University of Manchester, says that the outcome is “bad news” for accelerator physics and the applications that it fosters, particularly in medical physics. “It is completely at odds with UK priorities across all industrial strategy growth-driving areas, while also eliminating skills pipelines pivotal to a wide range of sectors and eroding the UK’s long-held position as a global scientific leader.”

Astronomy woes

Astronomy is another area that is bearing the brunt of the cuts. The UK contribution to the e-MERLIN network of seven radio telescopes, which includes the iconic Lovell telescope at Jodrell Bank in northern England, is also ear-marked for cancellation. Its funding will now run out in 2028 and the move not only threatens e-MERLIN but also the future of Jodrell Bank , which the Royal Astronomical Society calls a “deeply troubling development”.

Catherine Haymans, Astronomer Royal for Scotland, says she is “absolutely devastated” for those working on e-MERLIN. “This is a short-sighted move, to save a tiny fraction of the overall UK science budget,” she says. They are now considering contacting the new Department for Business, Innovation, Science and Trade to reverse the decision.

Other astronomy cuts include the UK withdrawal from the James Clerk Maxwell Telescope located in Hawaii as well as 20% cuts for the UK’s Square Kilometre Array Regional Centre and activities at the Vera C Rubin Observatory in Chile, which recently began a 10-year survey of the universe.

Jim Wild, president of the Royal Astronomical Society, notes the cuts are “devastating news” for UK astronomy. “At a time when technological innovation is crucial to our country’s prospects, discarding unique, globally significant observatories threatens both our scientific future and the inspiration of future generations of astronomers,” adds Wild.

Michele Dougherty, executive chair of the STFC, who is also Astronomer Royal, says that the situation requires “tough, but necessary decisions”.

“After listening to our community we have protected core discovery research within PPAN, through a more focused portfolio that safeguards postdoctoral researchers, protects PhD opportunities and maintains the UK’s international leadership.” adds Dougherty, who stepped down as president of the IOP in January over the conflict of interest with her position at the STFC. “These are never easy choices, but we have made what we feel are the right decisions to bring STFC to a sustainable financial position by 2029/30″.

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Bridging borders in medical physics: guidance, challenges and opportunities

Tami Freeman — Wed, 10 Dec 2025 14:00:03 +0000

History in the making The Bayeux Tapestry is on display at the British Museum in London until July 2027 but you can view it for free online thanks to advanced optical imaging techniques. (Courtesy: © La Fabrique de patrimoines en Normandie, Antoine Cazin)

A few years ago, I was lucky enough to see the Bayeux Tapestry – the famous embroidered cloth depicting the Norman invasion of England in 1066. More than 900 years old, this historic piece of art is only 50 cm wide but more than 68 m long. It’s also extremely fragile, which why I was astonished when I heard that the Bayeux Tapestry was going to leave its home in Normandy and be transported across the English Channel to the UK.

The loan of the artwork, which was agreed between former British prime minister Keir Starmer and French president Emmanuel Macron last year, has now taken place. The tapestry arrived under police escort on 10 July and will be on display at the British Museum in London from September 2026 until July 2027. It is the first time the tapestry has been back in England, the country where this linen cloth was originally made.

I’m fascinated by how non-invasive optical techniques have been crucial in advancing our understanding of the tapestry
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So what’s all this got to with physics? Well, I’m fascinated by how physics – and specifically, non-invasive optical techniques – have been crucial in advancing our understanding of the tapestry and its historical significance. Thanks to physics-based equipment developed by hi-tech manufacturers, we’ve learned about how the Bayeux Tapestry was initially made, what damage it subsequently suffered, how it was repaired, and the nature of its current condition.

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Such information is vital not only for increasing our historical awareness, but also for current conservators who want to understand the tapestry’s underlying condition and find out how to preserve it for future generations. And before the pedants write in, yes I know that while it’s known as the Bayeux Tapestry, technically it’s an embroidery. That means it was created by stitching woollen threads onto a linen backing, which is helpful to know when reviewing the physics involved.

Optical sleuthing

The beauty of using optical methods to study the Bayeux Tapestry is that they are non-destructive and non-intrusive – and so can typically be applied in situ. In 2017 a three-year project was started, in which conservationists used high-resolution 2D imaging, photogrammetry, multimodal scanning and advanced image reconstruction techniques to determine the tapestry’s condition and conservation needs. The project revealed considerable information about how this artwork was created and modified over time.

Thanks to these high-resolution images, we now have a single digital map of the entire tapestry, making it possible to zoom in and look at individual threads. It’s yielded information such as the width of stitches and the positions where the wool threads cross the original linen background. As a result, historians now believe the tapestry was made by a single group of embroiderers, who – knowing the skills that existed at the time – were probably based in Canterbury, UK.

Techniques such as infrared spectroscopy and fluorescent and reflection ultraviolet imaging have revealed information about what’s underneath the surface of the tapestry
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From the size and direction of the stitches, we also think the outlines of the figures were stitched first, with the shapes filled in afterwards using coloured wools in a strict, specific order. Meanwhile, techniques such as infrared spectroscopy and fluorescent and reflection ultraviolet imaging have revealed information about what’s underneath the surface of the tapestry. In particular, they’ve located the presence of stains such as glue, wax (dripped from candles that lit the tapestry) and even oil from the hands of people who touched it.

Infrared light passing through the dark-coloured wools have also revealed original sketch lines that were drawn on the linen base before the wool stitching started. It reveals the original artist’s draft, likely to be someone familiar with manuscript drawing – perhaps an illuminator of religious books.

Successful trip The Bayeux Tapestry was transported from Normandy to London in a climate-controlled crate – the journey having been sanctioned only because conservationists had pain-stakingly imaged, protected and studied the embroidered cloth. (Courtesy: © Trustees of the British Museum)

3D imaging with photogrammetry

Researchers in France, led by Stéphane Le Mouélic from Nantes University, who originally did a PhD in astrophysics, have also used computer software to combine more than 440 overlapping 2D photos taken from multiple angles to create a detailed 3D model of the Bayeux Tapestry (J. Cult. Heritage 71 211).

It digitally “irons out” all the sags and wrinkles in the line fabric, recreating the original, “flat” tapestry and allowing the original physical shape of the artwork to be revealed for the first time. The 3D model can be viewed for free at the Bayeux Museum website, allowing historians, researchers and members of the public to study it without having to handle the delicate material.

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Physics-based techniques have also allowed us to deal with the fact that parts of the fabric have been repaired over the last 900 plus years. Some of those repairs used non-authentic dyes and colours, while others covered up the original stitching. But using computer vision and image processing, threads that were added later can be subtracted digitally, providing a clearer, corrected view of what the original tapestry looked like.

Finally, optical tools can help keep the tapestry safe for future generations. Museum curators need to know if the cloth is sagging, tearing, or changing shape over time. Instead of putting heavy tools on the cloth, lasers can scan the cloth to accurately map of the contours of its surface. By repeating this exercise every few years, conservationists can spot if any part of the cloth has stretched or sagged, enabling minor problems to be rectified before they end up causing significant damage.

Without the huge amount of investigative and restorative work carried out, the Bayeux Tapestry would never have been allowed to make the journey to London
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In 2025 Le Monde newspaper reported that experts had, over the previous five years, meticulously documented 24,204 stains, 9646 holes and 30 tears in the artwork. Without the huge amount of investigative and restorative work carried out, the Bayeux Tapestry would never have been allowed to make this year’s journey to London. Advanced and detailed optical measurement has “de-risked” the tapestry’s trip.

Tickets to the British Museum exhibition are reportedly being snapped up faster than those for Glastonbury. So if you don’t get to see the tapestry in person, feel free to marvel at this wonderful historical artwork by checking out the interactive online digital copy. It really is physics and history in the making.

The post The Bayeux Tapestry: how optical techniques have let this artwork come home appeared first on Physics World.

Can a 16-year-old really understand quantum teleportation?

No Author — Wed, 29 Jul 2026 14:30:37 +0000

Quantum theory is one of humanity’s great intellectual achievements, radically transforming our understanding of nature at the deepest level while delivering unprecedented technological advances. We have thus always felt it a great pity that most young people never get the opportunity to engage with the theory at a substantive level.

The solid-state physicist David Mermin, who has studied the fundamentals of quantum mechanics, once memorably wrote of quantum theory: “We now know that the Moon is demonstrably not there when nobody looks”. It was a comment that certainly captures the imagination, but it is difficult to appreciate what he meant meant without engaging with the mathematics that lies behind it.

In an attempt to see if we could change that, we ran our first Quantum in Pictures programme at the University of Hertfordshire earlier this month. A five-day, in-person course, it was attended by about 45 students aged 16–18 and was built around Quantum Pictorialism – a diagrammatic approach to quantum theory pioneered by Bob Coecke from the University of Oxford and collaborators.

Seeing for real Bob Coecke using his pictorial approach to the subject (Courtesy: Shanti Pise and Leron Borsten)

The crucial point is that the pictures aren’t illustrations of some more fundamental mathematics hidden underneath. The pictures are the mathematics. A rigorous graphical calculus built from spider diagrams enables students to reason directly about quantum processes. Since this diagrammatic formulation is fully equivalent to the usual Hilbert space formalism, the students were doing quantum mechanics for real.

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We felt truly privileged to share the mysteries of quantum mechanics with a fantastically friendly, interested and diverse cohort from schools across south-east England. What struck me was how readily they engaged with the material: asking excellent (and sometimes rather challenging) questions, debating ideas and working collaboratively through the problem-solving sessions.

The graphical problems proved particularly popular, with repeated cries for “more spider diagrams!”. The course was deliberately ambitious, but by the end, they were able to work through the complete quantum teleportation protocol. Indeed, one student was confident enough to get up and reason through it for the whole class (something we certainly would not have dared to do at their age).

As Maya, a year-12 student from Highams Park Sixth Form in London, put it: “I really enjoyed seeing how ideas in quantum physics could be explained through simple pictures and diagrams. I was surprised that concepts like quantum teleportation, which seemed very complicated at first, could become much easier to understand through this approach. The programme has made me even more interested in studying physics and exploring quantum theory in the future.”

The approach also worked for students without a traditional mathematics or physics background, such as Andrew, a year-12 student from Sir John Lawes School in Harpenden.

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“The programme was captivating,” he said. “The concept of using diagrams was innovative and explained things in a logical manner to help me understand topics such as quantum teleportation. The programme showed the stark differences between classical and quantum physics through real-world examples, enriched by talks from industry experts and pioneers with different backgrounds.”

Muhammad Hamza Waseem, who helped develop the programme and joined us on the final day, captured the atmosphere perfectly. “I found the enthusiasm, curiosity, and irreverence of the students very inspiring,” he said, “and I hope that they take the same spirit into their university education and beyond.”

That sense of joy and excitement was, for me, the lesson of the week. We’ve been thoroughly convinced that quantum theory isn’t intrinsically beyond the reach of curious 16-year-olds. We just need to give them the right mathematical language. The next step is an optional graduate-level exam, which will put that claim to the test. Watch this space.

The authors would like to thank staff, researchers and students from the University of Hertfordshire who volunteered their time to make the programme possible. They are also grateful to Ian Loffler, Bob Coecke and Muhammad Hamza Waseem for their support and inspiring contributions.

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Can we compare Donald Trump’s health chief to Soviet science boss Trofim Lysenko?

Robert P Crease — Wed, 10 Dec 2025 11:00:15 +0000

The US has turned Trofim Lysenko into a hero.

Born in 1898, Lysenko was a Ukrainian plant breeder, who in 1927 found he could make pea and grain plants develop at different rates by applying the right temperatures to their seeds. The Soviet news organ Pravda was enthusiastic, saying his discovery could make crops grow in winter, turn barren fields green, feed starving cattle and end famine.

Despite having trained as a horticulturist, Lysenko rejected the then-emerging science of genetics in favour of Lamarckism, according to which organisms can pass on acquired traits to offspring. This meshed well with the Soviet philosophy of “dialectical materialism”, which sees both the natural and human worlds as evolving not through mechanisms but environment.

Stalin took note of Lysenko’s activities and had him installed as head of key Soviet science agencies. Once in power, Lysenko dismissed scientists who opposed his views, cancelled their meetings, funded studies of discredited theories, and stocked committees with loyalists. Although Lysenko had lost his influence by the time Stalin died in 1953 – with even Pravda having turned against him – Soviet agricultural science had been destroyed.

A modern parallel

Lysenko’s views and actions have a resonance today when considering the activities of Robert F Kennedy Jr, who was appointed by Donald Trump as secretary of the US Department of Health and Human Services in February 2025. Of course, Trump has repeatedly sought to impose his own agenda on US science, with his destructive impact outlined in a detailed report published by the Union of Concerned Scientists in July 2025.

Last May Trump signed executive order 14303, “Restoring Gold Standard Science”, which blasts scientists for not acting “in the best interests of the public”. He has withdrawn the US from the World Health Organization (WHO), ordered that Federal-sponsored research fund his own priorities, redefined the hazards of global warming, and cancelled the US National Climate Assessment (NSA), which had been running since 2000.

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But after Trump appointed Kennedy, the assault on science continued into US medicine, health and human services. In what might be called a philosophy of “political materialism”, Kennedy fired all 17 members of the Advisory Committee on Immunization Practices of the US Centers for Disease Control and Prevention (CDC), cancelled nearly $500m in mRNA vaccine contracts, hired a vaccine sceptic to study its connection with autism despite numerous studies that show no connection, and ordered the CDC to revise its website to reflect his own views on the cause of autism.

In his 2021 book The Real Anthony Fauci: Bill Gates, Big Pharma, and the Global War on Democracy and Public Health, Kennedy promotes not germ theory but what he calls “miasma theory”, according to which diseases are prevented by nutrition and lifestyle.

Divergent stories

Of course, there are fundamental differences between the 1930s Soviet Union and the 2020s United States. Stalin murdered and imprisoned his opponents, while the US administration only defunds and fires them. Stalin and Lysenko were not voted in, while Trump came democratically to power, with elected representatives confirming Kennedy. Kennedy has also apologized for his most inflammatory remarks, though Stalin and Lysenko never did (nor does Trump for that matter).

What’s more, Stalin’s and Lysenko’s actions were more grounded in apparent scientific realities and social vision than Trump’s or Kennedy’s. Stalin substantially built up much of the Soviet science and technology infrastructure, whose dramatic successes include launching the first Earth satellite Sputnik in 1957. Though it strains credulity to praise Stalin, his vision to expand Soviet agricultural production during a famine was at least plausible and its intention could be portrayed as humanitarian. Lysenko was a scientist, Kennedy is not.

As for Lysenko, his findings seemed to carry on those of his scientific predecessors. Experimentally, he expanded the work of Russian botanist Ivan Michurin, who bred new kinds of plants able to grow in different regions. Theoretically, his work connected not only with dialectical materialism but also with that of the French naturalist Jean-Baptiste Lamarck, who claimed that acquired traits can be inherited.

Trump and Kennedy are off-the-wall by comparison. Trump has called climate change a con job and hoax and seeks to stop research that says otherwise. In 2019 he falsely stated that Hurricane Dorian was predicted to hit Alabama, then ordered the National Oceanic and Atmospheric Administration to issue a statement supporting him. Trump has said he wants the US birth rate to rise and that he will be the “fertilization president”, but later fired fertility and IVF researchers at the CDC.

As for Kennedy, he has said that COVID-19 “is targeted to attack Caucasians and Black people” and that Ashkenazi Jews and Chinese are the most immune (he disputed the remark, but it’s on video). He has also sought to retract a 2025 vaccine study from the Annals of Internal Medicine (178 1369) that directly refuted his views on autism.

The critical point

US Presidents often have pet scientific projects. Harry Truman created the National Science Foundation, Dwight D Eisenhower set up NASA, John F Kennedy started the Apollo programme, while Richard Nixon launched the Environmental Protection Agency (EPA) and the War on Cancer. But it’s one thing to support science that might promote a political agenda and another to quash science that will not.

One ought to be able to take comfort in the fact that if you fight nature, you lose – except that the rest of us lose as well. Thanks to Lysenko’s actions, the Soviet Union lost millions of tons of grain and hundreds of herds of cattle. The promise of his work evaporated and Stalin’s dreams vanished.

Lysenko, at least, was motivated by seeming scientific promise and social vision; the US has none. Trump has damaged the most important US scientific agencies, destroyed databases and eliminated the EPA’s research arm, while Kennedy has replaced health advisory committees with party loyalists.

While Kennedy may not last his term – most Trump Cabinet officials don’t – the paths he has sent science policy on surely will. For Trump and Kennedy, the policy seems to consist only of supporting pet projects. Meanwhile, cases of measles in the US have reached their highest level in three decades, the seas continue to rise and the climate is changing. It is hard to imagine how enemy agents could damage US science more effectively.

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+ Bringing physics down to Earth through rocket science + https://physicsworld.com/a/bringing-physics-down-to-earth-through-rocket-science/ + Wed, 29 Jul 2026 10:00:53 +0000 + + + + https://physicsworld.com/?p=129175 + Keith Cooper reviews It’s (Just) Rocket Science: Exploring Physics Through Spaceflight Missions by Trisha Muro

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Diagnosing brain cancer without a biopsy

Lorna Brigham — Wed, 10 Dec 2025 09:19:15 +0000

Many catalysts are made using core-shell nanoparticles, in which the core is a structurally important or inexpensive material and the thin shell surrounding it is an expensive metal such as platinum. Since catalytic reactions occur on the surface, this helps to reduce the amount of platinum required and therefore lowers costs. Crystal structures are described based on the smallest repeating unit of the crystal (the unit cell) using the Bravais lattice system. Three important crystal structures are face-centred cubic (fcc, atoms at the corners and faces of a cube), body-centred cubic (bcc, atoms at the corners and centre of a cube), and hexagonal close-packed (hcp, a hexagonal arrangement of atoms).

Different materials have different crystal structures; for example, platinum is fcc, many alloys are bcc, and magnesium and zinc are hcp. In core–shell nanoparticles, differences between the crystal structures of the core and shell mean that the atoms do not line up perfectly. This mismatch creates strain, which can significantly affect catalytic performance. In this work, the researchers explored how a platinum shell grows on a different crystal structure in a process known as heteroepitaxy.

They studied platinum shells (Pt, fcc) grown on cores made of ruthenium (Ru, hcp), palladium–copper (PdCu, bcc), and specially synthesised ruthenium with an fcc structure. It was found that each system accommodates the atomic mismatch differently. In hcp/fcc particles, some areas lined up coherently while others contained defects called dislocations, which formed networks in particles smaller than 10 nm. In bcc/fcc particles, both the core and shell stretched or compressed to fit together. In fcc/fcc particles, the matching crystal structures aligned more readily, but twin defects formed in which one region mirrored another.

Overall, this study shows that the way a Pt shell grows on a nanoparticle core is determined by a balance between the energies of the interface, shell, and core, with the system naturally adopting the lowest-energy configuration. These findings could help scientists achieve atomic-precision interfacial engineering, controlling the catalytic, mechanical, and electrical properties of core-shell nanoparticles.

Read the full article

Ultra-sensitive detection of microRNA in intraocular fluid using optical fiber sensing technology for central nervous system lymphoma diagnosis

Yanqi Ge et al 2025 Rep. Prog. Phys. 88 070502

Atomic-scale 3D insights into heteroepitaxial mechanisms in hcp/fcc, bcc/fcc, and fcc/fcc core–shell nanoparticles

Xilong Mu et al 2026 Rep. Prog. Phys. 89 068002

Do you want to learn more about this topic?

Theoretical and computational tools to model multistable gene regulatory networks by Federico Bocci, Dongya Jia, Qing Nie, Mohit Kumar Jolly and José Onuchic (2023)

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PLP-Logo-2.png, find out more. Single metal nanoparticles: optical detection, spectroscopy and applications by P Zijlstra and M Orrit (2011)

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5f electrons and the mystery of δ-plutonium

Lorna Brigham — Wed, 10 Dec 2025 09:18:58 +0000

Plutonium is considered a fascinating element. It was first chemically isolated in 1941 at the University of California, but its discovery was hidden until after the Second World War. There are six distinct allotropic phases of plutonium with very different properties. At ambient pressure, continuously increasing the temperature converts the room-temperature, simple monoclinic a phase through five phase transitions, the final one occurring at approximately 450°C.

The delta (δ) phase is perhaps the most interesting allotrope of plutonium. δ-plutonium is technologically important, has a very simple crystal structure, but its electronic structure has been debated for decades. Researchers have attempted to understand its anomalous behaviour and how the properties of δ-plutonium are connected to the 5f electrons.

The 5f electrons are found in the actinide group of elements which includes plutonium. Their behaviour is counterintuitive. They are sensitive to temperature, pressure and composition, and behave in both a localised manner, staying close to the nucleus and in a delocalised (itinerant) manner, more spread out and contributing to bonding. Both these states can support magnetism depending on actinide element. The 5f electrons contribute to δ-phase stability, anomalies in the material’s volume and bulk modulus, and to a negative thermal expansion where the δ-phase reduces in size when heated.

Research group from Lawrence Livermore National Laboratory. Left to right: Lorin Benedict, Alexander Landa, Kyoung Eun Kweon, Emily Moore, Per Söderlind, Christine Wu, Nir Goldman, Randolph Hood and Aurelien Perron. Not in image: Babak Sadigh and Lin Yang (Courtesy: Blaise Douros/Lawrence Livermore National Laboratory)

In this work, the researchers present a comprehensive model to predict the thermodynamic behaviour of δ-plutonium, which has a face-centred cubic structure. They use density functional theory, a computational technique that explores the overall electron density of the system and incorporate relativistic effects to capture the behaviour of fast-moving electrons and complex magnetic interactions. The model includes a parameter-free orbital polarization mechanism to account for orbital-orbital interactions, and incorporates anharmonic lattice vibrations and magnetic fluctuations, both transverse and longitudinal modes, driven by temperature-induced excitations. Importantly, it is shown that negative thermal expansion results from magnetic fluctuations.

This is the first model to integrate electronic effects, magnetic fluctuations, and lattice vibrations into a cohesive framework that aligns with experimental observations and semi-empirical models such as CALPHAD. It also accounts for fluctuating states beyond the ground state and explains how gallium composition influences thermal expansion. Additionally, the model captures the positive thermal expansion behaviour of the high-temperature epsilon phase, offering new insight into plutonium’s complex thermodynamics.

+ https://physicsworld.com/?p=129495 + By reshaping quasicrystals with carefully designed defects, researchers can create and control stable twisting beams of light in new ways.

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Scientists explain why ‘seeding’ clouds with silver iodide is so efficient

Isabelle Dumé — Wed, 10 Dec 2025 08:58:07 +0000

Silver iodide crystals have long been used to “seed” clouds and trigger precipitation, but scientists have never been entirely sure why the material works so well for that purpose. Researchers at TU Wien in Austria are now a step closer to solving the mystery thanks to a new study that characterized surfaces of the material in atomic-scale detail.

“Silver iodide has been used in atmospheric weather modification programs around the world for several decades,” explains Jan Balajka from TU Wien’s Institute of Applied Physics, who led this research. “In fact, it was chosen for this purpose as far back as the 1940s because of its atomic crystal structure, which is nearly identical to that of ice – it has the same hexagonal symmetry and very similar distances between atoms in its lattice structure.”

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The basic idea, Balajka continues, originated with the 20^th-century American atmospheric scientist Bernard Vonnegut, who suggested in 1947 that introducing small silver iodide (AgI) crystals into a cloud could provide nuclei for ice to grow on. But while Vonnegut’s proposal worked (and helped to inspire his brother Kurt’s novel Cat’s Cradle), this simple picture is not entirely accurate. The stumbling block is that nucleation occurs at the surface of a crystal, not inside it, and the atomic structure of an AgI surface differs significantly from its interior.

A task that surface science has solved

To investigate further, Balajka and colleagues used high-resolution atomic force microscopy (AFM) and advanced computer simulations to study the atomic structure of 2‒3 nm diameter AgI crystals when they are broken into two pieces. The team’s measurements revealed that the surfaces of both freshly cleaved structures differed from those found inside the crystal.

More specifically, team member Johanna Hütner, who performed the experiments, explains that when an AgI crystal is cleaved, the silver atoms end up on one side while the iodine atoms appear on the other. This has implications for ice growth, because while the silver side maintains a hexagonal arrangement that provides an ideal template for the growth of ice layers, the iodine side reconstructs into a rectangular pattern that no longer lattice-matches the hexagonal symmetry of ice crystals. The iodine side is therefore incompatible with the epitaxial growth of hexagonal ice.

“Our works solves this decades-long controversy of the surface vs bulk structure of AgI, and shows that structural compatibility does matter,” Balajka says.

Difficult experiments

According to Balajka, the team’s experiments were far from easy. Many experimental methods for studying the structure and properties of material surfaces are based on interactions with charged particles such as electrons or ions, but AgI is an electrical insulator, which “excludes most of the tools available,” he explains. Using AFM enabled them to overcome this problem, he adds, because this technique detects interatomic forces between a sharp tip and the surface and does not require a conductive sample.

Another problem is that AgI is photosensitive and decomposes when exposed to visible light. While this property is useful in other contexts – AgI was a common ingredient in early photographic plates – it created complications for the TU Wien team. “Conventional AFM setups make use of optical laser detection to map the topography of a sample,” Balajka notes.

To avoid destroying their sample while studying it, the researchers therefore had to use a non-contact AFM based on a piezoelectric sensor that detects electrical signals and does not require optical readout. They also adapted their setup to operate in near-darkness, using only red light while manipulating the Ag to ensure that stray light did not degrade the samples.

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The computational modelling part of the work introduced yet another hurdle to overcome. “Both Ag and I are atoms with a high number of electrons in their electron shells and are thus highly polarizable,” Balajka explains. “The interaction between such atoms cannot be accurately described by standard computational modelling methods such as density functional theory (DFT), so we had to employ highly accurate random-phase approximation (RPA) calculations to obtain reliable results.”

Highly controlled conditions

The researchers acknowledge that their study, which is detailed in Science Advances, was conducted under highly controlled conditions – ultrahigh vacuum, low pressure and temperature and a dark environment – that are very different from those that prevail inside real clouds. “The next logical step for us is therefore to confirm whether our findings hold under more representative conditions,” Balajka says. “We would like to find out whether the structure of AgI surfaces is the same in air and water, and if not, why.”

The researchers would also like to better understand the atomic arrangement of the rectangular reconstruction of the iodine surface. “This would complete the picture for the use of AgI in ice nucleation, as well as our understanding of AgI as a material overall,” Balajka says.

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+ Cold radioactive molecules offer a tabletop route to new physics + https://physicsworld.com/a/cold-radioactive-molecules-offer-a-tabletop-route-to-new-physics/ + Tue, 28 Jul 2026 16:42:01 +0000 + + + + + https://physicsworld.com/?p=129498 + Nuclear symmetry violations could show up in molecules containing pear-shaped radium nuclei

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Slow spectroscopy sheds light on photodegradation

No Author — Tue, 09 Dec 2025 17:22:00 +0000

A new type of “photonic multi-lane highway” that can carry multiple topologically-protected optical signals at once – without the need for a bulky insulator – has been demonstrated by researchers in China. The technology, which relies on a new type of material called a photonic valley half-semimetal to achieve topological protection, is currently at the prototype stage. However, the researchers believe that, if fabrication challenges can be addressed, the combination of spatial efficiency and topological robustness could be promising for future photonic technologies.

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In the past 20 years, photonic topological insulators have become widespread for connections in devices such as on-chip photonic circuits because their edge modes can only conduct light in one direction and are therefore are inherently immune from scattering off imperfections. However, the protected edge mode of a topological insulator comes at a cost: the bulk must have an optical band gap, which means it must be opaque to the relevant frequency. Meanwhile, the photonic analogue of another concept from electronics has also become popular in optical waveguides. Gapless photonic semimetals – analogous to graphene – can be placed between topologically distinct optical insulators to broaden the guided modes, but non-guiding insulating claddings are still required.

To address the fundamental trade-off between spatial efficiency and topological protection in conventional topological waveguides, researchers in the group of Che Ting Chan at the Hong Kong University of Science and Technology in China and their collaborators introduced a novel photonic structure called a photonic valley half-semimetal. Here, the valley degree of freedom refers to inequivalent local energy extrema in momentum space, which can be used as independent degrees of freedom for transport. Crucially, a single photonic valley half-semimetal plays a dual role via its two valley channels: one valley acts as a gapless semimetal that enables waveguiding, while the other functions as a topological insulator that provides a topological barrier for the corresponding valley mode in adjacent regions.

Four stacked layers

The researchers designed a waveguide comprising four stacked layers of a honeycomb structure made from interconnected rods of the magnetic material yttrium iron garnet, which interfered with the propagating photons. By altering the diameters of the rods or the magnetic field, the researchers constructed four inequivalent photonic valley half-semimetal domains and arranged them in a specific periodic sequence. This creates adjacent domains that mutually insulate each other.

Xiaohan Cui is lead author on a paper in Nature that describes the research. She explains that the underlying topological physics is similar to that in a traditional photonic topological insulator.

“The important difference lies in how the mode is spatially implemented,” she says, “In a conventional photonic topological-insulator waveguide, two gapped bulk domains meet at an interface, and the propagating mode is tightly localized to that interface. Most of the surrounding insulating material remains inert, serving only as cladding.”

In the present configuration, however, the researchers were able to use the blocked valley as topological protection for unidirectional propagation in the neighbouring domain, and utilize this to create a four-lane highway, with two lanes in each direction, that could guide signals around sharp bends and through constrictions without backscattering or inter-lane crosstalk:

No wasted space

“The architecture transforms the usual narrow interface state into a set of directly adjacent, large-area waveguiding lanes. Consequently, no region of the device is ‘wasted’ as inert cladding,” explains Cui.

The team’s current device works for microwave radiation but the team says that the design could be adapted and extended to operate at higher frequencies.

“The present experiment is a proof of principle demonstration at microwave frequencies, so one clear next step is to move the concept towards higher-frequency, chip-scale integrated photonics platforms, thereby paving the way toward ultra-compact topological photonic circuitry,” says Cui.

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The researchers believe application in the terahertz regime should be possible using magnetized semiconductors such as indium antimonide. However, non-reciprocal applications at higher frequencies could be challenging owing to the weakness of magnetic effects.

“The major experimental challenges will be to realize these higher-frequency designs while managing geometric complexity, fabrication tolerances, and propagation loss, and ensuring efficient coupling with practical sources, detectors and other photonic components,” she explains.

Quantum optician Mahmoud Jalali Mehrabad of Massachusetts Institute of Technology believes the work brings an important issue into focus. “A paper doesn’t always have to have the perfect solution as long as it highlights and really streamlines a key problem…To me this paper does that,” he says. “Spatial efficiency has been a problem in topological physics and the question is why? Is there any other way to destroy this trade-off? It shouldn’t be a side problem in the supplementary material of a paper – this is a big problem.” Whether or not the researchers can make their own solution viable, he says, “time will tell”.

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Fermilab opens new building dedicated to Tevatron pioneer Helen Edwards

Michael Banks — Tue, 09 Dec 2025 14:59:37 +0000

Fermilab has officially opened a new building named after the particle physicist Helen Edwards. Officials from the lab and the US Department of Energy (DOE) opened the Helen Edwards Engineering Research Center at a ceremony held on 5 December. The new building is the lab’s largest purpose-built lab and office space since the lab’s iconic Wilson Hall, which was completed in 1974.

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Construction of the Helen Edwards Engineering Research Center began in 2019 and was completed three years later. The centre is an 7500 m² multi-story lab and office building that is adjacent and connected to Wilson Hall.

The new centre is designed as a collaborative lab where engineers, scientists and technicians design, build and test technologies across several areas of research such as neutrino science, particle detectors, quantum science and electronics.

The centre also features cleanrooms, vibration-sensitive labs and cryogenic facilities in which the components of the near detector for the Deep Underground Neutrino Experiment will be assembled and tested.

A pioneering spirit

With a PhD in experimental particle physics from Cornell University, Edwards was heavily involved with commissioning the university’s 10 GeV electron synchrotron. In 1970 Fermilab’s director Robert Wilson appointed Edwards as associate head of the lab’s booster section and she later became head of the accelerator division.

While at Fermilab, Edwards’ primary responsibility was designing, constructing, commissioning and operating the Tevatron, which led to the discoveries of the top quark in 1995 and the tau neutrino in 2000.

Edwards retired in the early 1990s but continued to work as guest scientists at Fermilab and officially switched the Tevatron off during a ceremony held on 30 September 2011. Edwards died in 2016.

Darío Gil, the undersecretary for science at the DOE says that Edwards’ scientific work “is a symbol of the pioneering spirit of US research”.

“Her contributions to the Tevatron and the lab helped the US become a world leader in the study of elementary particles,” notes Gil. “We honour her legacy by naming this research centre after her as Fermilab continues shaping the next generation of research using [artificial intelligence], [machine learning] and quantum physics.”

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Memristors could measure a single quantum of resistance

Isabelle Dumé — Tue, 09 Dec 2025 09:52:54 +0000

A proposed new way of defining the standard unit of electrical resistance would do away with the need for strong magnetic fields when measuring it. The new technique is based on memristors, which are programmable resistors originally developed as building blocks for novel computing architectures, and its developers say it would considerably simplify the experimental apparatus required to measure a single quantum of resistance for some applications.

Electrical resistance is a physical quantity that represents how much a material opposes the flow of electrical current. It is measured in ohms (Ω), and since 2019, when the base units of the International System of Units (SI) were most recently revised, the ohm has been defined in terms of the von Klitzing constant h/e², where h and e are the Planck constant and the charge on an electron, respectively.

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To measure this resistance with high precision, scientists use the fact that the von Klitzing constant is related to the quantized change in the Hall resistance of a two-dimensional electron system (such as the one that forms in a semiconductor heterostructure) in the presence of a strong magnetic field. This quantized change in resistance is known as the quantum Hall effect (QHE), and in a material like GaAs or AlGaAs, it shows up at fields of around 10 Tesla. Generating such high fields typically requires a superconducting electromagnet, however.

A completely different approach

Researchers connected to a European project called MEMQuD are now advocating a completely different approach. Their idea is based on memristors, which are programmable resistors that “remember” their previous resistance state even after they have been switched off. This previous resistance state can be changed by applying a voltage or current.

In the new work, a team led by Gianluca Milano of Italy’s Istituto Nazionale di Ricerca Metrologia (INRiM); Vitor Cabral of the Instituto Português da Qualidade; and Ilia Valov of the Institute of Electrochemistry and Energy Systems at the Bulgarian Academy of Sciences studied a device based on memristive nanoionics cells made from conducting filaments of silver. When an electrical field is applied to these filaments, their conductance changes in distinct, quantized steps.

The MEMQuD team reports that the quantum conductance levels achieved in this set-up are precise enough to be exploited as intrinsic standard values. Indeed, a large inter-laboratory comparison confirmed that the values deviated by just -3.8% and 0.6% from the agreed SI values for the fundamental quantum of conductance, G₀, and 2G₀, respectively. The researchers attribute this precision to tight, atomic-level control over the morphology of the nanochannels responsible for quantum conductance effects, which they achieved by electrochemically polishing the silver filaments into the desired configuration.

A national metrology institute condensed into a microchip

The researchers say their results are building towards a concept known as an “NMI-in-a-chip�� – that is, condensing the services of a national metrology institute into a microchip. “This could lead to measuring devices that have their resistance references built-in directly into the chip,” says Milano, “so doing away with complex measurements in laboratories and allowing for devices with zero-chain traceability – that is, those that do not require calibration since they have embedded intrinsic standards.”

Yuma Okazaki of Japan’s National Institute of Advanced Industrial Science and Technology (AIST), who was not involved in this work, says that the new technique could indeed allow end users to directly access a quantum resistance standard.

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“Notably, this method can be demonstrated at room temperature and under ambient conditions, in contrast to conventional methods that require cryogenic and vacuum equipment, which is expensive and require a lot of electrical power,” Okazaki says. “If such a user-friendly quantum standard becomes more stable and its uncertainty is improved, it could lead to a new calibration scheme for ensuring the accuracy of electronics used in extreme environments, such as space or the deep ocean, where traditional quantum standards that rely on cryogenic and vacuum conditions cannot be readily used.”

The MEMQuD researchers, who report their work in Nature Nanotechnology, now plan to explore ways to further decrease deviations from the agreed SI values for G₀ and 2G₀. These include better material engineering, an improved measurement protocol, and strategies for topologically protecting the memristor’s resistance.

The post Memristors could measure a single quantum of resistance appeared first on Physics World.

+ + + https://physicsworld.com/?p=129488 + CERN’s ALPHA collaboration pins down the ground-state hyperfine splitting of antihydrogen within four parts per million

The post Matter-antimatter symmetry measurement sets new precision record appeared first on Physics World.

Oak Ridge Quantum Science Center prioritizes joined-up thinking, multidisciplinary impacts

No Author — Mon, 08 Dec 2025 14:00:07 +0000

Travis Humble is a research leader who’s thinking big, dreaming bold, yet laser-focused on operational delivery. The long-game? To translate advances in fundamental quantum science into a portfolio of enabling technologies that will fast-track the practical deployment of quantum computers for at-scale scientific, industrial and commercial applications.

As director of the Quantum Science Center (QSC) at Oak Ridge National Laboratory (ORNL) in East Tennessee, Humble and his management team are well placed to transform that research vision into scientific, economic and societal upside. Funded to the tune of $115 million through its initial five-year programme (2020–25), QSC is one of five dedicated National Quantum Information Science Research Centers (NQISRC) within the US Department of Energy (DOE) National Laboratory system.

Validation came in spades last month when, despite the current turbulence around US science funding, QSC was given follow-on DOE backing of $125 million over five years (2025–30) to create “a new scientific ecosystem” for fault-tolerant, quantum-accelerated high-performance computing (QHPC). In short, QSC will target the critical research needed to amplify the impact of quantum computing through its convergence with leadership-class exascale HPC systems.

“Our priority in Phase II QSC is the creation of a common software ecosystem to host the compilers, programming libraries, simulators and debuggers needed to develop hybrid-aware algorithms and applications for QHPC,” explains Humble. Equally important, QSC researchers will develop and integrate new techniques in quantum error correction, fault-tolerant computing protocols and hybrid algorithms that combine leading-edge computing capabilities for pre- and post-processing of quantum programs. “These advances will optimize quantum circuit constructions and accelerate the most challenging computational tasks within scientific simulations,” Humble adds.

Classical computing, quantum opportunity

At the heart of the QSC programme sits ORNL’s leading-edge research infrastructure for classical HPC, a capability that includes Frontier, the first supercomputer to break the exascale barrier and still one of the world’s most powerful. On that foundation, QSC is committed to building QHPC architectures that take advantage of both quantum computers and exascale supercomputing to tackle all manner of scientific and industrial problems beyond the reach of today’s HPC systems alone.

“Hybrid classical-quantum computing systems are the future,” says Humble. “With quantum computers connecting both physically and logically to existing HPC systems, we can forge a scalable path to integrate quantum technologies into our scientific infrastructure.”

Quantum acceleration ORNL’s current supercomputer, Frontier, was the first high-performance machine to break the exascale barrier. Plans are in motion for a next-generation supercomputer, Discovery, to come online at ORNL by 2028. (Courtesy: Carlos Jones/ORNL, US DOE)

Industry partnerships are especially important in this regard. Working in collaboration with the likes of IonQ, Infleqtion and QuEra, QSC scientists are translating a range of computationally intensive scientific problems – quantum simulations of exotic matter, for example – onto the vendors’ quantum computing platforms, generating excellent results out the other side.

“With our broad representation of industry partners,” notes Humble, “we will establish a common framework by which scientific end-users, software developers and hardware architects can collaboratively advance these tightly coupled, scalable hybrid computing systems.”

It’s a co-development model that industry values greatly. “Reciprocity is key,” Humble adds. “At QSC, we get to validate that QHPC can address real-world research problems, while our industry partners gather user feedback to inform the ongoing design and optimization of their quantum hardware and software.”

Quantum impact

Innovation being what it is, quantum computing systems will continue to trend on an accelerating trajectory, with more qubits, enhanced fidelity, error correction and fault-tolerance key reference points on the development roadmap. Phase II QSC, for its part, will integrate five parallel research thrusts to advance the viability and uptake of QHPC technologies.

The collaborative software effort, led by ORNL’s Vicente Leyton, will develop openQSE, an adaptive, end-to-end software ecosystem for QHPC systems and applications. Yigit Subasi from Los Alamos National Laboratory (LANL) will lead the hybrid algorithms thrust, which will design algorithms that combine conventional and quantum methods to solve challenging problems in the simulation of model materials.

Meanwhile, the QHPC architectures thrust, under the guidance of ORNL’s Chris Zimmer, will co-design hybrid computing systems that integrate quantum computers with leading-edge HPC systems. The scientific applications thrust, led by LANL’s Andrew Sornberger, will develop and validate applications of quantum simulation to be implemented on prototype QHPC systems. Finally, ORNL’s Michael McGuire will lead the thrust to establish experimental baselines for quantum materials that ultimately validate QHPC simulations against real-world measurements.

Longer term, ORNL is well placed to scale up the QHPC model. After all, the laboratory is credited with pioneering the hybrid supercomputing model that uses graphics processing units in addition to conventional central processing units (including the launch in 2012 of Titan, the first supercomputer of this type operating at over 10 petaFLOPS).

“The priority for all the QSC partners,” notes Humble, “is to transition from this still-speculative research phase in quantum computing, while orchestrating the inevitable convergence between quantum technology, existing HPC capabilities and evolving scientific workflows.”

Collaborate, coordinate, communicate

Much like its NQISRC counterparts (which have also been allocated further DOE funding through 2030), QSC provides the “operational umbrella” for a broad-scope collaboration of more than 300 scientists and engineers from 20 partner institutions. With its own distinct set of research priorities, that collective activity cuts across other National Laboratories (Los Alamos and Pacific Northwest), universities (among them Berkeley, Cornell and Purdue) and businesses (including IBM and IQM) to chart an ambitious R&D pathway addressing quantum-state (qubit) resilience, controllability and, ultimately, the scalability of quantum technologies.

“QSC is a multidisciplinary melting pot,” explains Humble, “and I would say, alongside all our scientific and engineering talent, it’s the pooled user facilities that we are able to exploit here at Oak Ridge and across our network of partners that gives us our ‘grand capability’ in quantum science [see box, “Unique user facilities unlock QSC opportunities”]. Certainly, when you have a common research infrastructure, orchestrated as part a unified initiative like QSC, then you can deliver powerful science that translates into real-world impacts.”

Unique user facilities unlock QSC opportunities

Neutron insights ORNL director Stephen Streiffer tours the linear accelerator tunnel at the Spallation Neutron Source (SNS). QSC scientists are using the SNS to investigate entirely new classes of strongly correlated materials that demonstrate topological order and quantum entanglement. (Courtesy: Alonda Hines/ORNL, US DOE)

Deconstructed, QSC’s Phase I remit (2020–25) spanned three dovetailing and cross-disciplinary research pathways: discovery and development of advanced materials for topological quantum computing (in which quantum information is stored in a stable topological state – or phase – of a physical system rather than the properties of individual particles or atoms); development of next-generation quantum sensors (to characterize topological states and support the search for dark matter); as well as quantum algorithms and simulations (for studies in fundamental physics and quantum chemistry).

Underpinning that collective effort: ORNL’s unique array of scientific user facilities. A case in point is the Spallation Neutron Source (SNS), an accelerator-based neutron-scattering facility that enables a diverse programme of pure and applied research in the physical sciences, life sciences and engineering. QSC scientists, for example, are using SNS to investigate entirely new classes of strongly correlated materials that demonstrate topological order and quantum entanglement – properties that show great promise for quantum computing and quantum metrology applications.

“The high-brightness neutrons at SNS give us access to this remarkable capability for materials characterization,” says Humble. “Using the SNS neutron beams, we can probe exotic materials, recover the neutrons that scatter off of them and, from the resultant signals, infer whether or not the materials exhibit quantum properties such as entanglement.”

While SNS may be ORNL’s “big-ticket” user facility, the laboratory is also home to another high-end resource for quantum studies: the Center for Nanophase Material Science (CNMS), one of the DOE’s five national Nanoscience Research Centers, which offers QSC scientists access to specialist expertise and equipment for nanomaterials synthesis; materials and device characterization; as well as theory, modelling and simulation in nanoscale science and technology.

Thanks to these co-located capabilities, QSC scientists pioneered another intriguing line of enquiry – one that will now be taken forward elsewhere within ORNL – by harnessing so-called quantum spin liquids, in which electron spins can become entangled with each other to demonstrate correlations over very large distances (relative to the size of individual atoms).

In this way, it is possible to take materials that have been certified as quantum-entangled and use them to design new types of quantum devices with unique geometries – as well as connections to electrodes and other types of control systems – to unlock novel physics and exotic quantum behaviours. The long-term goal? Translation of quantum spin liquids into a novel qubit technology to store and process quantum information.

SNS, CNMS and Oak Ridge Leadership Computing Facility (OLCF) are DOE Office of Science user facilities.

When he’s not overseeing the technical direction of QSC, Humble is acutely attuned to the need for sustained and accessible messaging. The priority? To connect researchers across the collaboration – physicists, chemists, material scientists, quantum information scientists and engineers – as well as key external stakeholders within the DOE, government and industry.

“In my experience,” he concludes, ”the ability of the QSC teams to communicate efficiently – to understand each other’s concepts and reasoning and to translate back and forth across disciplinary boundaries – remains fundamental to the success of our scientific endeavours.”

Further information

Listen to the Physics World podcast: Oak Ridge’s Quantum Science Center takes a multidisciplinary approach to developing quantum materials and technologies

Scaling the talent pipeline in quantum science

The next generation Quantum science graduate students and postdoctoral researchers present and discuss their work during a poster session at the fifth annual QSC Summer School. Hosted at Purdue University in April this year, the school is one of several workforce development efforts supported by QSC. (Courtesy: Dave Mason/Purdue University)

With an acknowledged shortage of skilled workers across the quantum supply chain, QSC is doing its bit to bolster the scientific and industrial workforce. Front-and-centre: the fifth annual QSC Summer School, which was held at Purdue University in April this year, hosting 130 graduate students (the largest cohort to date) through an intensive four-day training programme.

The Summer School sits as part of a long-term QSC initiative to equip ambitious individuals with the specialist domain knowledge and skills needed to thrive in a quantum sector brimming with opportunity – whether that’s in scientific research or out in industry with hardware companies, software companies or, ultimately, the end-users of quantum technologies in key verticals like pharmaceuticals, finance and healthcare.

“While PhD students and postdocs are integral to the QSC research effort, the Summer School exposes them to the fundamental ideas of quantum science elaborated by leading experts in the field,” notes Vivien Zapf, a condensed-matter physicist at Los Alamos National Laboratory who heads up QSC’s advanced characterization efforts.

“It’s all about encouraging the collective conversation,” she adds, “with lots of opportunities for questions and knowledge exchange. Overall, our emphasis is very much on training up scientists and engineers to work across the diversity of disciplines needed to translate quantum technologies out of the lab into practical applications.”

The programme isn’t for the faint-hearted, though. Student delegates kicked off this year’s proceedings with a half-day of introductory presentations on quantum materials, devices and algorithms. Next up: three and a half days of intensive lectures, panel discussions and poster sessions covering everything from entangled quantum networks to quantum simulations of superconducting qubits.

Many of the Summer School’s sessions were also made available virtually on Purdue’s Quantum Coffeehouse Live Stream on YouTube – the streamed content reaching quantum learners across the US and further afield. Lecturers were drawn from the US National Laboratories, leading universities (such as Harvard and Northwestern) and the quantum technology sector (including experts from IBM, PsiQuantum, NVIDIA and JPMorganChase).

The post Oak Ridge Quantum Science Center prioritizes joined-up thinking, multidisciplinary impacts appeared first on Physics World.

+ Geophysicist identifies a maximum practical viscosity + https://physicsworld.com/a/geophysicist-identifies-a-maximum-practical-viscosity/ + Mon, 27 Jul 2026 08:00:40 +0000 + + + + + https://physicsworld.com/?p=129474 + Boundary between materials that flow and those that don’t could shed light on Earth’s early history

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So you want to install a wind turbine? Here’s what you need to know

No Author — Mon, 08 Dec 2025 11:00:42 +0000

Here’s how the game works:

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1. Enter a word guess – in this game the word has six letters.
2. After submitting your guess, each letter in the guessed word is coloured to provide feedback: +
  - Green: The letter is correct and is in the correct position in the target word.
  - Yellow: The letter is correct but is in the wrong position in the target word.
  - Grey: The letter is not in the target word at all.
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3. Using this colour feedback, refine your next guess.
4. Continue guessing until you correctly identify the hidden word(s) or run out of attempts.
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As we cycle, I discover that the project – located in Forstenrieder Park – is the joint effort of four local councils and two “citizen-energy” groups, who’ve worked together for the last five years to plan and start building the six turbines. Each tower will be 166 m high and the rotor blades will be 80 m long, with the plan being for them to start operating in 2027.

I’ve never thought of Munich as a particularly windy city, but at the height at which the blades operate, there’s always a steady, reliable flow of wind
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I’ve never thought of Munich as a particularly windy city. But tour leader Dieter Maier, who’s a climate adviser to Neuried council, explains that at the height at which the blades operate, there’s always a steady, reliable flow of wind. In fact, each turbine has a designed power output of 6.5 MW and will deliver a total of 10 GWh in energy over the course of a year.

Practical questions

Cycling around, I’m excited to think that a single turbine could end up providing the entire electricity demand for Neuried. But installing wind turbines involves much more than just the technicalities of generating electricity. How do you connect the turbines to the grid? How do you ensure planes don’t fly into the turbines? What about wildlife conservation and biodiversity?

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At one point of our tour, we cycle round a 90-degree bend in the forest and I wonder how a huge, 80 m-long blade will be transported round that kind of tight angle? Trees will almost certainly have to be felled to get the blade in place, which sounds questionable for a supposedly green project. Fortunately, project leaders have been working with the local forest manager and conservationists, finding ways to help improve the local biodiversity despite the loss of trees.

As a representative of BUND (one of Germany’s biggest conservation charities) explains on the tour, a natural, or “unmanaged”, forest consists of a mix of areas with a higher or lower density of trees. But Forstenrieder Park has been a managed forest for well over a century and is mostly thick with trees. Clearing trees for the turbines will therefore allow conservationists to grow more of the bushes and plants that currently struggle to find space to flourish.

Cut and cover Trees in Forstenrieder Park have had to be chopped down to provide room for new wind turbines to be installed, but the open space will let conservationists grow plants and bushes to boost biodiversity. (Courtesy: Janina Moereke)

To avoid endangering birds and bats native to this forest, meanwhile, the turbines will be turned off when the animals are most active, which coincidentally corresponds to low wind periods in Munich. Insurance costs have to be factored in too. Thankfully, it’s quite unlikely that a turbine will burn down or get ice all over its blades, which means liability insurance costs are low. But vandalism is an ever-present worry.

In fact, at the end of our bike tour, we’re taken to a local wind turbine that is already up and running about 13 km further south of Forstenrieder Park. This turbine, I’m disappointed to discover, was vandalized back in 2024, which led to it being fenced off and video surveillance cameras being installed.

But for all the difficulties, I’m excited by the prospect of the wind turbines supporting the local energy needs. I can’t wait for the day when I’m on my balcony, solar panels at my side, sipping a cup of tea made with water boiled by electricity generated by the rotor blades I can see turning round and round on the horizon.

The post So you want to install a wind turbine? Here’s what you need to know appeared first on Physics World.

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If you want a clue to the answer, read the article here.

Fancy some more? Check out our puzzles page.

The post Word wave puzzle no.6 appeared first on Physics World.

Galactic gamma rays could point to dark matter

Hamish Johnston — Fri, 05 Dec 2025 14:21:05 +0000

Excess radiation Gamma-ray intensity map excluding components other than the halo, spanning approximately 100° in the direction of the centre of the Milky Way. The blank horizontal bar is the galactic plane area, which was excluded from the analysis to avoid strong astrophysical radiation. (Courtesy: Tomonori Totani/The University of Tokyo)

Gamma rays emitted from the halo of the Milky Way could be produced by hypothetical dark-matter particles. That is the conclusion of an astronomer in Japan who has analysed data from NASA’s Fermi Gamma-ray Space Telescope. The energy spectrum of the emission is what would be expected from the annihilation of particles called WIMPs. If this can be verified, it would mark the first observation of dark matter via electromagnetic radiation.

Since the 1930s astronomers have known that there is something odd about galaxies, galaxy clusters and larger structures in the universe. The problem is that there is not nearly enough visible matter in these objects to explain their dynamics and structure. A rotating galaxy, for example, should be flinging out its stars because it does not have enough self-gravitation to hold itself together.

Today, the most popular solution to this conundrum is the existence of a hypothetical substance called dark matter. Dark-matter particles would have mass and interact with each other and normal matter via the gravitational force, gluing rotating galaxies together. However, the fact that we have never observed dark matter directly means that the particles must rarely, if ever, interact via the other three forces.

Annihilating WIMPs

The weakly interacting massive particle (WIMP) is a dark-matter candidate that interacts via the weak nuclear force (or a similarly weak force). As a result of this interaction, pairs of WIMPs are expected to occasionally annihilate to create high-energy gamma rays and other particles. If this is true, dense areas of the universe such as galaxies should be sources of these gamma rays.

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Now, Tomonori Totani of the University of Tokyo has analysed data from the Fermi telescope and identified an excess of gamma rays emanating from the halo of the Milky Way. What is more, Totani’s analysis suggests that the energy spectrum of the excess radiation (from about 10−100 GeV) is consistent with hypothetical WIMP annihilation processes.

“If this is correct, to the extent of my knowledge, it would mark the first time humanity has ‘seen’ dark matter,” says Totani. “This signifies a major development in astronomy and physics,” he adds.

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While Totani is confident of his analysis, his conclusion must be verified independently. Furthermore, work will be needed to rule out conventional astrophysical sources of the excess radiation.

Catherine Heymans, who is Astronomer Royal for Scotland told Physics World, “I think it’s a really nice piece of work, and exactly what should be happening with the Fermi data”. The research is described in Journal of Cosmology and Astroparticle Physics. Heymans describes Totani’s paper as “well written and thorough”.

The post Galactic gamma rays could point to dark matter appeared first on Physics World.

+ + + + https://physicsworld.com/?p=129481 + Cross calibration combines data from 25 satellites

The post GPS particle detectors track space radiation over two decades appeared first on Physics World.

Simple feedback mechanism keeps flapping flyers stable when hovering

Isabelle Dumé — Fri, 05 Dec 2025 09:00:59 +0000

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Join us for an in‑depth conversation with Simon Cherry, former editor‑in‑chief of Physics in Medicine & Biology (PMB), as he shares his expert perspective on the evolving landscape of medical physics research, molecular imaging, and non-invasive imaging technologies. Drawing on decades of leadership in biomedical imaging and academic publishing, Simon will reflect on major advances shaping the field, define the characteristics of high‑impact imaging research, and highlight how PMB continues to support rigorous, influential scientific work through its editorial standards and peer‑review practices.

This session will additionally spotlight the research of Xinchen (Alison) Deng, a finalist of the PMB 2024 Early Career Award. Attendees will gain insights into her contributions to the advanced medical imaging community, such as photon-counting CT for clinical applications and how her work supports broader advances in medical physics and X-ray/CT imaging research.

Simon will also discuss what makes early‑career research stand out and share strategies for researchers aiming to increase the visibility, reach, and long‑term impact of their publications within competitive scientific journals.

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Left to right: Carol Clark, Simon Cherry, Xinchen (Alison) Deng

Moderator

Carol Clark, Publisher, Physics in Medicine & Biology

Speakers

Simon R Cherry, PhD received his BSc (Hons) in physics with astronomy from University College London in 1986 and a PhD in medical physics from the Institute of Cancer Research, University of London in 1989. Simon is currently Distinguished Research Professor in the Departments of Biomedical Engineering and Radiology at UC Davis and Professor of Total-Body Imaging at King’s College London. Simon’s research interests centre around biomedical imaging. His major contributions have been in developing systems for positron emission tomography (PET), including designing the microPET scanner for small-animal imaging, the earliest examples of simultaneous PET and MRI studies and co-leading the EXPLORER consortium that developed the world’s first total-body PET scanner. Simon is a Fellow of the Royal Society and Member of the U.S. National Academy of Engineering and National Academy of Inventors. He has received several international awards including the Society of Nuclear Medicine and Molecular Imaging Cassen Prize in 2022. He served as editor-in-chief of the journal Physics in Medicine & Biology from 2011–2020. Simon is the author of more than 350 peer-reviewed journal articles, review articles and book chapters in the field of biomedical imaging. He is also lead author of the widely-used textbook Physics in Nuclear Medicine.

Xinchen (Alison) Deng, PhD, is a diagnostic imaging physics resident at The Ohio State University. Her research focuses on advancing photon-counting CT for clinical applications, including multi-contrast imaging, early disease detection, detector optimization, and AI-based improvements in image quality. Before beginning the residency, Xinchen (Alison) was a postdoctoral fellow in medical physics at the University of Victoria, where she worked with Magdalena Bazalova-Carter and collaborated with Redlen Technologies on the optimization of photon-counting detectors and the clinical applications of spectral CT. She received her PhD in medical physics from the University of British Columbia, where she applied Raman spectroscopy, machine learning, and explainable AI to study radiation treatment response in cancer cells and tissues. Her broader research background spans photon-counting CT, spectral X-ray imaging, Raman spectroscopy, radiotherapy response assessment, and AI-driven image and data analysis. Her photon-counting CT research has been featured in the Physics in Medicine & Biology Early Career Researcher Focus Collection. She is a finalist for the PMB Early Career Researcher Award.

About this journal
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Physics in Medicine & Biology. The international journal of biomedical physics and engineering, published by IOP Publishing on behalf of the Institute of Physics and Engineering in Medicine (IPEM)

Editor-in-chief: Katia Parodi, Ludwig-Maximilians University, Munich, Germany

The post Shaping the field of medical imaging: a fireside chat with Simon R Cherry and Xinchen Deng appeared first on Physics World.

Building a quantum future using topological phases of matter and error correction

Hamish Johnston — Thu, 04 Dec 2025 14:55:09 +0000

This episode of the Physics World Weekly podcast features Tim Hsieh of Canada’s Perimeter Institute for Theoretical Physics. We explore some of today’s hottest topics in quantum science and technology – including topological phases of matter; quantum error correction and quantum simulation.

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Our conversation begins with an exploration of the quirky properties quantum matter and how these can be exploited to create quantum technologies. We look at the challenges that must be overcome to create large-scale quantum computers; and Hsieh reveals which problem he would solve first if he had access to a powerful quantum processor.

This interview was recorded earlier this autumn when I had the pleasure of visiting the Perimeter Institute and speaking to four physicists about their research. This is the third of those conversations to appear on the podcast.

The first interview in this series from the Perimeter Institute was with Javier Toledo-Marín, “Quantum computing and AI join forces for particle physics”; and the second was with Bianca Dittrich, “Quantum gravity: we explore spin foams and other potential solutions to this enduring challenge“.

Simulating quantum systems is something that classical computers struggle with. Not surprisingly, quantum computers are expected to do a much better job – particularly when a quantum-computer’s architecture is designed to solve a specific type of physics problem.

My guest in this episode of the Physics World Weekly podcast is Ross Jenkinson of the UK’s University of Manchester. He talks about the challenges and rewards of using quantum computers in particle physics – a field where classical supercomputers can struggle to simulate simple systems.

We also explore how quantum information theory is being combined with Einstein’s general theory of relativity to shed light on the nature of space and time.

This episode is supported by the APS Global Physics Summit, which takes place on 15–20 March, 2026, in Denver, Colorado, and online.

The post Building a quantum future using topological phases of matter and error correction appeared first on Physics World.

The post Quarks and qubits: how quantum computing could transform particle physics appeared first on Physics World.

Generative AI model detects blood cell abnormalities

Tami Freeman — Thu, 04 Dec 2025 13:00:09 +0000

Generative classification The CytoDiffusion classifier accurately identifies a wide range of blood cell appearances and detects unusual or rare blood cells that may indicate disease. The diagonal grid elements display original images of each cell type, while the off-diagonal elements show heat maps that provide insight into the model’s decision-making rationale. (Courtesy: Simon Deltadahl)

The shape and structure of blood cells provide vital indicators for diagnosis and management of blood disease and disorders. Recognizing subtle differences in the appearance of cells under a microscope, however, requires the skills of experts with years of training, motivating researchers to investigate whether artificial intelligence (AI) could help automate this onerous task. A UK-led research team has now developed a generative AI-based model, known as CytoDiffusion, that characterizes blood cell morphology with greater accuracy and reliability than human experts.

Conventional discriminative machine learning models can match human performance at classifying cells in blood samples into predefined classes. But discriminative models, which learn to recognise cell images based on expert labels, struggle with never-before-seen cell types and images from differing microscopes and staining techniques.

To address these shortfalls, the team – headed up at the University of Cambridge, University College London and Queen Mary University of London – created CytoDiffusion around a diffusion-based generative AI classifier. Rather than just learning to separate cell categories, CytoDiffusion models the full range of blood cell morphologies to provide accurate classification with robust anomaly detection.

“Our approach is motivated by the desire to achieve a model with superhuman fidelity, flexibility and metacognitive awareness that can capture the distribution of all possible morphological appearances,” the researchers write.

Authenticity and accuracy

For AI-based analysis to be adopted in the clinic, it’s essential that users trust a model’s learned representations. To assess whether CytoDiffusion could effectively capture the distribution of blood cell images, the team used it to generate synthetic blood cell images. Analysis by experienced haematologists revealed that these synthetic images were near-indistinguishable from genuine images, showing that CytoDiffusion genuinely learns the morphological distribution of blood cells rather than using artefactual shortcuts.

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The researchers used multiple datasets to develop and evaluate their diffusion classifier, including CytoData, a custom dataset containing more than half a million anonymized cell images from almost 3000 blood smear slides. In standard classification tasks across these datasets, CytoDiffusion achieved state-of-the-art performance, matching or exceeding the capabilities of traditional discriminative models.

Effective diagnosis from blood smear samples also requires the ability to detect rare or previously unseen cell types. The researchers evaluated CytoDiffusion’s ability to detect blast cells (immature blood cells) in the test datasets. Blast cells are associated with blood malignancies such as leukaemia, and high detection sensitivity is essential to minimize false negatives.

In one dataset, CytoDiffusion detected blast cells with sensitivity and specificity of 0.905 and 0.962, respectively. In contrast, a discriminative model exhibited a poor sensitivity of 0.281. In datasets with erythroblasts as the abnormal cells, CytoDiffusion again outperformed the discriminative model, demonstrating that it can detect abnormal cell types not present in its training data, with the high sensitivity required for clinical applications.

Robust model

It’s important that a classification model is robust to different imaging conditions and can function with sparse training data, as commonly found in clinical applications. When trained and tested on diverse image datasets (different hospitals, microscopes and staining procedures), CytoDiffusion achieved state-of-the-art accuracy in all cases. Likewise, after training on limited subsets of 10, 20 and 50 images per class, CytoDiffusion consistently outperformed discriminative models, particularly in the most data-scarce conditions.

Another essential feature of clinical classification tasks, whether performed by a human or an algorithm, is knowing the uncertainty in the final decision. The researchers developed a framework for evaluating uncertainty and showed that CytoDiffusion produced superior uncertainty estimates to human experts. With uncertainty quantified, cases with high certainty could be processed automatically, with uncertain cases flagged for human review.

“When we tested its accuracy, the system was slightly better than humans,” says first author Simon Deltadahl from the University of Cambridge in a press statement. “But where it really stood out was in knowing when it was uncertain. Our model would never say it was certain and then be wrong, but that is something that humans sometimes do.”

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Finally, the team demonstrated CytoDiffusion’s ability to create heat maps highlighting regions that would need to change for an image to be reclassified. This feature provides insight into the model’s decision-making process and shows that it understands subtle differences between similar cell types. Such transparency is essential for clinical deployment of AI, making models more trustworthy as practitioners can verify that classifications are based on legitimate morphological features.

“The true value of healthcare AI lies not in approximating human expertise at lower cost, but in enabling greater diagnostic, prognostic and prescriptive power than either experts or simple statistical models can achieve,” adds co-senior author Parashkev Nachev from University College London.

CytoDiffusion is described in Nature Machine Intelligence.

The post Generative AI model detects blood cell abnormalities appeared first on Physics World.

Light pollution from satellite mega-constellations threaten space-based observations

Michael Banks — Thu, 04 Dec 2025 11:50:11 +0000

Photonics reimagined SmarAct and Akhetonics worked together to build a versatile optical test set-up to characterize next-generation photonic integrated circuits (PICs). SmarAct’s nanopositioning systems form the precision-motion core of the test workstation, while the positional reproducibility allows Akhetonics to map the full optical chip and evaluate large grids of test components rapidly and reliably. (Courtesy: Akhetonics)

German technology start-up Akhetonics is reimagining the future of high-performance computing (HPC), deploying its proprietary know-how in photonic-design automation and photonic integrated circuits (PICs) to realize the first all-optical digital computation devices. The end-game: an all-optical digital processor – what Akhetonics calls its reasoning processing unit (RPU) – that will fundamentally transform the way that data is processed, transmitted and stored at every level of the HPC stack.

While the anticipated upsides of photonic computing are compelling – think bandwidth scaling, energy-efficiency and reduced latency – the translation of Akhetonics’ R&D effort and early-stage PIC designs into at-scale implementation is still in its infancy. What’s evident even now, though, is that the start-up’s progress is being accelerated by collaboration, interdisciplinary expertise and innovation spanning photonic system design and precision-motion and control technologies.

Collaboration, co-development, customization

A case study in this regard is Akhetonics’ partnership with SmarAct, a German manufacturer and developer of specialist products for nano- and picometre-precise positioning, metrology and automated assembly. Both companies are shaping the future of photonics, albeit along complementary tracks: Akhetonics with its vision of a full-stack photonic computing architecture; SmarAct with a portfolio of enabling technologies that’s helping to make next-generation optical computing a practical proposition.

The two vendors began working together after an initial meeting four years ago at the European Conference on Optical Communication (ECOC 22) in Basel, Switzerland. Top of the Akhetonics shopping list: a versatile optical test system to characterize its advanced PICs.

Versatility is the key Leonardo Del Bino, Akhetonics’ CTO. (Courtesy: Akhetonics)

“There are off-the-shelf PIC characterization systems on the market, but they all impose constraints on our design options,” explains Leonardo Del Bino, co-founder and chief technology officer (CTO) at Akhetonics. “Instead, we teamed up with SmarAct to co-develop a compact and modular test architecture built to our exacting specifications. The resulting set-up gives us the flexibility to evaluate and optimize all sorts of innovative PIC designs.”

At the heart of the Akhetonics optical testing workstation sit two discrete nanopositioning subsystems: an XY-Rz chip platform (itself comprising three nanopositioning stages offering horizontal translation along the X and Y axes and rotation limited to the Z axis) and a Z-Rx-Ry “pivot” for an optical probe (where translation occurs only along the Z axis, with simultaneous angular rotation around the X and Y axes). The test set-up (which also incorporates a digital microscope for PIC inspection and alignment) can be used without restriction in every degree of freedom, with the two subsystems working in tandem to ensure precise multi-axis positioning for optical coupling and electro-optic characterization tasks.

On a more granular level, each nanopositioning subsystem is based on SmarAct positioners equipped with integrated optical encoders (SmarAct’s METIRIO® sensors with a resolution of 1 nm) along all six axes of motion. The first subsystem provides three degrees of freedom for lateral alignment (with 49 mm travel in both X and Y, 360° rotation around Rz and a unidirectional positional repeatability of ±40 nm per linear axis). The second subsystem provides vertical and angular alignment (with 31 mm travel in Z, ±5° tilt around Ry, ±45° rotation around Rz and a unidirectional positional repeatability of ±40 nm for the linear Z axis).

To evaluate new PIC designs, Akhetonics’ optical test routines focus primarily on measuring and minimizing insertion losses between input/output fibres and on-chip planar waveguides. Typical measurements include wavelength- and polarization-dependent coupling losses (for example, when a fibre array couples laser light into a series of on-chip grating couplers or when light is coupled from a planar waveguide back into an optical fibre). The subsequent integration of electrical probes into the test system (using two separate XYZ probe towers) supports electro-optic characterization of key on-chip building blocks like optical modulators and photodetectors.

“The requirements for the electro-optical testing are nothing crazy,” says Del Bino. On-chip electrical contacts are in the ballpark of 100 μm x 100 μm, so Akhetonics engineers need positional and alignment precision an order-of-magnitude better than that for their electrical probes. “On-chip optical testing is a different story,” he adds. “A fibre-waveguide mismatch of 1 μm means significant coupling losses, so we need positional accuracy and repeatability of tens of nm or less.”

The rewards of reciprocity

Operationally, the custom test system is the result of ongoing collaboration between the engineering team at Akhetonics and the product development team at SmarAct. After firming up performance requirements, the two vendors iterated back-and-forth with 3D CAD drawings before converging on a final agreed system design.

Line-of-sight Max Trippel, SmarAct’s business development manager for photonic applications. (Courtesy: SmarAct)

“We supplied the nanopositioning stages that form the precision-motion core of the workstation,” explains Max Trippel, SmarAct’s business development manager for photonic applications. Akhetonics then integrated these modules into its own test environment, including the fibre and fibre-array-unit holders; the required optical and electrical measurement equipment; and the software routines for photonic characterization. “This approach gives Akhetonics the flexibility to build exactly the test workflow it needs, while relying on a stable and repeatable positioning platform,” Trippel adds.

Crucially, the SmarAct software “ecosystem” and Python interface make it easy to integrate the nanopositioning stages within Akhetonics’ PIC test routines. That software application platform, known as the SmarAct Control and Process Environment (SCoPE), also creates opportunities for continuous process improvement and product innovation (for example, the ability to develop custom routines for fast calibration and alignment on all axes).

In this way, SCoPE will be a natural fit as Akhetonics transitions its PIC testing programme from an R&D setting through small-batch production runs and, ultimately, to volume manufacturing capability (see “SCoPE in brief”, below). “Our goal with SCoPE is to provide customers with easy access for system development, whether that’s for the testing or assembly of photonic components,” says Trippel. “SCoPE is a living platform and we’re constantly integrating novel functionalities and application-specific plug-ins as well as features to facilitate control of third-party devices.”

Strategically, the SmarAct-Akhetonics partnership is shaping up as a win-win for the long term, with the latter’s growth trajectory and evolving platform technologies feeding into SmarAct’s product development roadmap. “Our customers’ success is our success,” Trippel concludes. “Working in this way with Akhetonics and its peers means we have line-of-sight on ‘what’s next’ in photonic computing. Watch this space: the last word has not been spoken.”

SCoPE in brief

The SmarAct Control and Process Environment (SCoPE) is a modular and extensible software application platform that combines visual process modelling, Python scripting and hardware integration. SCoPE enables customers to develop, control and run automated processes in a unified environment that offers…

Reciprocal benefits The custom test system is the result of an ongoing collaboration between the engineering team at Akhetonics and the product development team at SmarAct. (Courtesy: SmarAct)

Katherine Courtney, chairs the Global Network on Sustainability in Space, and Alice Gorman from Flinders University in Adelaide, Australia, appeared on a Physics World Live panel discussion about the impact of space debris that was held on 10 November. A recording of the event is available here.
Process modelling and automation: visual drag-and-drop process editor enables intuitive creation, control and execution of automation workflows. Live process display gives users direct feedback during execution.
Python scripting backend: integrated Python scripting allows developers to extend workflows with custom logic, algorithms and third-party devices to create advanced automation scenarios. Package and dependency management are built-in.
Device control and hardware integration: native support for SmarAct hardware such as positioning systems, controllers, grippers and interferometers through specialized plug-ins.
Custom user interfaces: flexible Qt widget integration makes it possible to build tailored graphical user interfaces for specific applications.
Data visualization and imaging: configurable plotting widgets, real-time data visualization, process messaging and an integrated image processing pipeline support instant process feedback and image-based automation tasks.
Plug-in architecture: the modular plug-in system enables SmarAct and third parties to extend SCoPE with additional functions, algorithms, hardware integrations or communication interfaces.
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Physicists use a radioactive molecule’s own electrons to probe its internal structure

Isabelle Dumé — Thu, 04 Dec 2025 09:00:45 +0000

I am writing from Argentina as a researcher working within the country’s national scientific system. While discussions about science funding are often framed in terms of budgets and economic indicators, the reality is experienced in laboratories, offices and research facilities where scientific knowledge is produced.

Today, many of us in Argentina are witnessing a progressive deterioration of Argentine science, both in terms of infrastructure and human capital.

I am based at the Comisión Nacional de Energía Atómica (CNEA), where uncertainty has become routine. Hundreds of employees remain on temporary contracts that can be terminated without warning. On 1 July 2026, a total of 61 colleagues lost their jobs, with armed military police officers occupying the building to contain a peaceful employee protest. Beyond the immediate human cost, these dismissals are steadily dismantling scientific capabilities that have taken decades to build.

The impact became tangible when my colleague Paula Alderete, an experienced electron microscope specialist, lost her position. Alderete, who has published two papers with me, was responsible not only for operating a highly specialized instrument, but also for maintaining it and supporting dozens of research projects.

Without Paula Alderete’s expertise, our lab’s electron microscope has become largely unusable. It is a quiet reminder that scientific infrastructure depends as much on people as on expensive equipment.
+Faramarz S Gard

Without her expertise, the microscope has become largely unusable. Every morning I pass her empty desk on my way to the laboratory. It has become a quiet reminder that scientific infrastructure depends as much on people as on expensive equipment.

The deterioration extends beyond personnel. In my laboratory, an X-ray photoelectron spectroscopy (XPS) instrument worth more than $1m must sometimes be protected with plastic sheets because rainwater leaks through the roof.

Equipment designed to operate under tightly controlled environmental conditions is now exposed to circumstances that threaten its long-term reliability. Similar situations are becoming increasingly common across Argentina’s universities and research institutes as maintenance budgets shrink and infrastructure ages.

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Argentina has a scientific tradition that reaches far beyond its borders. The country has produced five Nobel laureates, including three in the sciences, and has made internationally recognized contributions to nuclear technology, medicine, agriculture, astronomy and materials science. Institutions such as CNEA, CONICET (Argentina’s national research council) and the national universities have trained generations of researchers whose work has strengthened international collaborations and advanced scientific knowledge worldwide.

Scientific systems rarely collapse through a single dramatic event. They decline incrementally: one technician dismissed, one laboratory left unrepaired, one instrument taken out of service, one young scientist deciding to build a career elsewhere. These individual losses accumulate into a weakening of scientific capacity that may take decades to rebuild.

When a country loses the expertise required to operate advanced laboratories or maintain unique scientific infrastructure, the consequences extend beyond national borders.
+Faramarz S Gard

This should concern more than Argentina. Modern science depends on international networks of researchers, shared facilities and long-term collaboration. When a country loses the expertise required to operate advanced laboratories or maintain unique scientific infrastructure, the consequences extend beyond national borders.

Damaged goods This X-ray photoelectron spectrometer at the author’s lab has to be protected from water leaking through the ceiling. (Courtesy: Faramarz S Gard)

Knowledge is lost, collaborations weaken, and opportunities for discovery diminish.scientific infrastructure is more than buildings and instruments; it is the people whose expertise gives those resources value. Once that expertise disappears, replacing it is far more difficult than preserving it.

The empty desk of a single scientist may seem insignificant, but multiplied across laboratories and institutions, it becomes a warning of how a research system is quietly dismantled. Argentina’s experience is therefore not only a national concern but also a reminder that scientific capacity, wherever it exists, is a global resource that is remarkably difficult to rebuild once lost.

I write this letter not only to describe a difficult situation but also to call attention to the broader consequences of sustained disinvestment in science. The international scientific community should recognize that the erosion of research systems in countries such as Argentina represents a loss not only for those nations but for global science itself.

Science is built by people, sustained by institutions, and enabled by infrastructure. Today, all three are under increasing strain in Argentina.

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Discovery of giant ‘exosatellite’ challenges our notion of what makes a moon

Keith Cooper — Wed, 22 Jul 2026 15:05:06 +0000

A possible “exosatellite” has been discovered 73 light years away. Bizarrely, it is roughly the size of Jupiter and orbiting a failed star called a brown dwarf, which in turn is orbiting the red dwarf star CD-35 2722.

This huge alien “moon” was found by the Very Large Telescope’s CRIRES+ spectroscopic instrument, which measured the Doppler shift in the brown dwarf’s light as the exosatellite gravitationally tugged on it. This is the same method used to discover the first known exoplanet around a Sun-like star, namely 51 Pegasi b, in 1995.

Only a handful of exosatellite candidates have been discovered thus far, with none being particularly convincing. This newly detected satellite, reported in Nature, is possibly the best of the bunch. The brown dwarf, known as CD-35 2722b, has a mass about 37 times greater than Jupiter and its exosatellite has a minimum mass of 90% that of Jupiter.

Moon, satellite or planet?

Planetary mass objects around brown dwarfs have been discovered before. Take the example of 2M1207b, which is an object up to six times more massive than Jupiter orbiting a brown dwarf, discovered in 2005 by the Very Large Telescope. Such objects have not been referred to previously as moons or satellites, so why now?

“This system is meaningfully different from 2M1207 because of the mass ratios and separations involved in CD-35 2722,” says Kevin Hoy, a PhD candidate at the European Southern Observatory and the Instituto de Estudios Astrofísicos in Chile, who led the discovery.

Whereas 2M1207b is approximately a quarter of the mass of its host brown dwarf and on a very wide orbit, possibly as long as 20,000 years, CD-35 2722b’s satellite has about 2.5% of the mass of its host brown dwarf and is on a much closer 170-day orbit.

There’s also the hierarchy of the system to consider. In the 2M1207 system, the brown dwarf doesn’t orbit anything, but in CD-35 2722 the brown dwarf is on a 5000-year-long orbit around its companion star. The candidate exosatellite therefore orbits something that orbits a star, just as a given moon in our Solar System orbits a planet that orbits a star. Since our Solar System has nothing like this brown dwarf–satellite combination, the language that we use to describe such objects is seemingly inadequate.

Mary Anne Limbach of the University of Michigan, who was not involved in this study, agrees that our nomenclature is increasingly ill-suited to the bizarre objects that we are discovering beyond our Solar System.

“Most people in the astronomical community would probably hesitate to call this an exomoon,” she tells Physics World. “But I think ‘exosatellite’ is appropriate. The field needs language for companions that do not neatly fit into the traditional categories of planets and moons, and ‘satellite’ seems to be the broader term that the field is gravitating towards.”

Forming exosatellites

Definitions are important, adds Limbach, because they allow us to distinguish between how otherwise similar objects formed.

The moons in our Solar System formed from debris discs encircling their parent planets. Material in the discs clumped together, forming cores that were then able to sweep up the remainder of the material. Astronomers refer to this as core accretion formation.

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“If I had to put money on it, I would doubt that the CD-35 2722b satellite formed via core accretion for several reasons,” says Hoy. These reasons include the size of the disc required to build such a massive satellite, the speed with which it would have done so (it is only 150 million years old) and its eccentric orbit. Moons born in situ around their parent typically adopt a more circular orbit.

Instead, Hoy suspects that the brown dwarf and its satellite collapsed directly out of a gas cloud in much the same way that stars do. “That would be my best guess,” he says.

The formation mechanism makes all the difference to Limbach, who opines that, “an object can reasonably be called a moon if it formed through a process analogous to the formation of the moons around the Solar System’s planets.”

Limbach cautions that since we only know the satellite’s minimum mass, we cannot yet rule out this being a binary system of two brown dwarfs. Either way, Limbach sees the system as being close to that of a binary giant planet. Our understanding of how giant planetary bodies and low-mass brown dwarfs form tells us that binary giant planets should be rare, “but the first emerging examples hint that they may not be,” says Limbach. These include about 40 pairs of rogue binary giant planets, called Jupiter Mass Binary Objects (JuMBOs), found by the James Webb Space Telescope in the Orion Nebula’s Trapezium star cluster.

Tip of the iceberg

Another unanswered question is how far down does CD-35 2722’s hierarchy go? Could the exosatellite have moons of its own?

“I think it’s definitely possible,” says Hoy, so long as they are on tight orbits so that gravitational tides cannot destabilize them. “Unfortunately such an object is likely impossible to detect with our current methods.”

However, our current methods could soon learn that CD-35 2722 is just the tip of the iceberg.

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“Looking at directly imaged planets and brown dwarfs is the most likely way to yield more exosatellites,” says Hoy, while also citing astrometry (looking for deviations in the motion of a star through space) and microlensing (where the gravity of an otherwise unseen exosatellite creates a temporary gravitational lens) as key techniques that could bring dividends.

Meanwhile, it is hoped that the European Space Agency’s PLATO mission, which will discover exoplanets via transits, will detect significantly large terrestrial moons once the mission launches at the beginning of 2027. All in all, we could be on the cusp of a new era of exomoon and exosatellite discovery.

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Quantum-scale thermodynamics offers a tighter definition of entropy

No Author — Wed, 03 Dec 2025 16:18:34 +0000

A new, microscopic formulation of the second law of thermodynamics for coherently driven quantum systems has been proposed by researchers in Switzerland and Germany. The researchers applied their formulation to several canonical quantum systems, such as a three-level maser. They believe the result provides a tighter definition of entropy in such systems, and could form a basis for further exploration.

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In any physical process, the first law of thermodynamics says that the total energy must always be conserved, with some converted to useful work and the remainder dissipated as heat. The second law of thermodynamics says that, in any allowed process, the total amount of heat (the entropy) must always increase.

“I like to think of work being mediated by degrees of freedom that we control and heat being mediated by degrees of freedom that we cannot control,” explains theoretical physicist Patrick Potts of the University of Basel in Switzerland. “In the macroscopic scenario, for example, work would be performed by some piston – we can move it.” The heat, meanwhile, goes into modes such as phonons generated by friction.

Murky at small scales

This distinction, however, becomes murky at small scales: “Once you go microscopic everything’s microscopic, so it becomes much more difficult to say ‘what is it that that you control – where is the work mediated – and what is it that you cannot control?’,” says Potts.

Potts and colleagues in Basel and at RWTH Aachen University in Germany examined the case of optical cavities driven by laser light, systems that can do work: “If you think of a laser as being able to promote a system from a ground state to an excited state, that’s very important to what’s being done in quantum computers, for example,” says Potts. “If you rotate a qubit, you’re doing exactly that.”

The light interacts with the cavity and makes an arbitrary number of bounces before leaking out. This emergent light is traditionally treated as heat in quantum simulations. However, it can still be partially coherent – if the cavity is empty, it can be just as coherent as the incoming light and can do just as much work.

In 2020, quantum optician Alexia Auffèves of Université Grenoble Alpes in France and colleagues noted that the coherent component of the light exiting a cavity could potentially do work. In the new study, the researchers embedded this in a consistent thermodynamic framework. They studied several examples and formulated physically consistent laws of thermodynamics.

In particular, they looked at the three-level maser, which is a canonical example of a quantum heat engine. However, it has generally been modelled semi-classically by assuming that the cavity contains a macroscopic electromagnetic field.

Work vanishes

“The old description will tell you that you put energy into this macroscopic field and that is work,” says Potts, “But once you describe the cavity quantum mechanically using the old framework then – poof! – the work is gone…Putting energy into the light field is no longer considered work, and whatever leaves the cavity is considered heat.”

The researchers new thermodynamic treatment allows them to treat the cavity quantum mechanically and to parametrize the minimum degree of entropy in the radiation that emerges – how much radiation must be converted to uncontrolled degrees of freedom that can do no useful work and how much can remain coherent.

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The researchers are now applying their formalism to study thermodynamic uncertainty relations as an extension of the traditional second law of thermodynamics. “It’s actually a trade-off between three things – not just efficiency and power, but fluctuations also play a role,” says Potts. “So the more fluctuations you allow for, the higher you can get the efficiency and the power at the same time. These three things are very interesting to look at with this new formalism because these thermodynamic uncertainty relations hold for classical systems, but not for quantum systems.”

“This [work] fits very well into a question that has been heavily discussed for a long time in the quantum thermodynamics community, which is how to properly define work and how to properly define useful resources,” says quantum theorist Federico Cerisola of the UK’s University of Exeter. “In particular, they very convincingly argue that, in the particular family of experiments they’re describing, there are resources that have been ignored in the past when using more standard approaches that can still be used for something useful.”

Cerisola says that, in his view, the logical next step is to propose a system – ideally one that can be implemented experimentally – in which radiation that would traditionally have been considered waste actually does useful work.

The research is described in Physical Review Letters.

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+ + + https://physicsworld.com/?p=129220 + Can you reconstruct this food-as-culture image in our interactive slide puzzle?

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Bring gravity back down to Earth: from giraffes and tree snakes to ‘squishy’ space–time

No Author — Wed, 03 Dec 2025 13:00:22 +0000

When I was five years old, my family moved into a 1930s semi-detached house with a long strip of garden. At the end of the garden was a miniature orchard of eight apple trees the previous owners had planted – and it was there that I, much like another significantly more famous physicist, learned an important lesson about gravity.

As I read in the shade of the trees, an apple would sometimes fall with a satisfying thunk into the soft grass beside me. Less satisfyingly, they sometimes landed on my legs, or even my head – and the big cooking apples really hurt. I soon took to sitting on old wooden pallets crudely wedged among the higher branches. It was not comfortable, but at least I could return indoors without bruises.

The effects of gravity become common sense so early in life that we rarely stop to think about them past childhood. In his new book Crush: Close Encounters with Gravity, James Riordon has decided to take us back to the basics of this most fundamental of forces. Indeed, he explores an impressively wide range of topics – from why we dream of falling and why giraffes should not exist (but do), to how black holes form and the existence of “Planet 9”.

Riordon, a physicist turned science writer, makes for a deeply engaging author. He is not afraid to put himself into the story, introducing difficult concepts through personal experience and explaining them with the help of everything including the kitchen sink, which in his hands becomes an analogue for a black hole.

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Gravity as a subject can easily be both too familiar and too challenging. In Riordon’s words, “Things with mass attract each other. That’s really all there is to Newtonian gravity.” While Albert Einstein’s theory of general relativity, by contrast, is so intricate that it takes years of university-level study to truly master. Riordon avoids both pitfalls: he manages to make the simple fascinating again, and the complex understandable.

He provides captivating insights into how gravity has shaped the animal kingdom, a perspective I had never much considered. Did you know that tree snakes have their hearts positioned closer to their heads than their land-based cousins? I certainly didn’t. The higher placement ensures a steady blood flow to the brain, even when the snake is climbing vertically. It is one of many examples that make you look again at the natural world with fresh eyes.

Riordon’s treatment of gravity in Einstein’s abstract space–time is equally impressive, perhaps unsurprisingly, as his previous books include Very Easy Relativity and Relatively Easy Relativity. Riordon takes a careful, patient approach – though I have never before heard general relativity reduced to “space–time is squishy”. But why not? The phrase sticks and gives us a handhold as we scale the complications of the theory. For those who want to extend the challenge, a mathematical background to the theory is provided in an appendix, and every chapter is well referenced and accompanied with suggestions for further reading.

If anything, I found myself wanting more examples of gravity as experienced by humans and animals on Earth, as opposed to in the context of the astronomical realm. I found these down-to-earth chapters the most fascinating: they formed a bridge between the vast and the local, reminding us that the same force that governs the orbits of galaxies also brings an apple to the ground. This may be a reaction only felt by astronomers like me, who already spend their days looking upward. I can easily see how the balance Riordon chose is necessary for someone without that background, and Einstein’s gravity does require galactic scales to appreciate, after all.

Crush is a generally uncomplicated and pleasurable read. The anecdotes can sometimes be a little long-winded and there are parts of the book that are not without challenge. But it is pitched perfectly for the curious general reader and even for those dipping their toes into popular science for the first time. I can imagine an enthusiastic A-level student devouring it; it is exactly the kind of book I would have loved at that age. Even if some of it would have gone over my head, Riordon’s enthusiasm and gift for storytelling would have kept me more than interested, as I sat up on that pallet in my favourite apple tree.

I left that house, and that tree, a long time ago, but just a few miles down the road from where I live now stands another, far more famous apple tree. In the garden of Woolsthorpe Manor near Grantham, Newton is said to have watched an apple fall. From that small event, he began to ask the questions that reshaped his and our understanding of the universe. Whether or not the story is true hardly matters – Newton was constantly inspired by the natural world, so it isn’t improbable, and that apple tree remains a potent symbol of curiosity and insight.

“[Newton] could tell us that an apple falls, and how quickly it will do it. As for the question of why it falls, that took Einstein to answer,” writes Riordon. Crush is a crisp and fresh tour through a continuum from orchards to observatories, showing that every planetary orbit, pulse of starlight and even every apple fall is part of the same wondrous story.

2025 MIT Press 288pp £27hb

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Ice XXI appears in a diamond anvil cell

Isabelle Dumé — Wed, 03 Dec 2025 12:00:45 +0000

As I was strolling through Belfast’s Titanic Quarter last summer, I discovered with delight a road called Bell’s Theorem Crescent. It’s named in honour of the Belfast-born physicist John Bell, best known for his eponymous theorem. Despite not being as embedded in popular culture as Schrödinger’s cat, his theorem will certainly ring a bell (forgive the pun) with most physicists.

The story goes back to 1935 when Albert Einstein, Boris Podolsky and Nathan Rosen (EPR) came up with their now-famous thought experiment, which was designed to show that quantum mechanics was, as a description of nature, incomplete. In the EPR scenario, non-local influences can affect the measurement outcomes performed on spatially separated particles.

Given how odd that seemed, some physicists invoked what are known as “hidden variables” to get rid of these non-local correlations and restore local realism. It was in 1964, while working at the CERN particle-physics lab, that Bell showed that no local hidden-variable theory can be compatible with the predictions of quantum mechanics.

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This result – Bell’s theorem – is something I was familiar with but I had paid little attention to where it had originally appeared. As I discovered, it was published in a paper called “On the Einstein Podolsky Rosen paradox” in the journal Physics (3 195) in 1964. Also known as Physics Physique Физика, this little-known publication existed only from 1964 to 1968. In fact, Bell’s theorem is the most important result published in it.

The journal was set up by two physicists at Bell Laboratories in the US – Bernd Matthias and future Nobel laureate Philip Anderson. According to A Mind Over Matter – Andrew Zangwill’s 2021 biography of Anderson – they were not too happy with conventional physics journals. “The referees,” Anderson said, “often did a bad job, the editors took too long to make decisions, and too much wrong physics got published.”

Those are complaints you’ll still hear in coffee breaks at most physics conferences today, and they prompted Matthias to contact the media magnate Robert Maxwell, who’d founded Oxford-based publishing house Pergamon Press. Maxwell had figured out that scientific publishing could be a very lucrative business so he helped the two physicists to set up the journal.

A publishing experiment

In their first editorial, Anderson and Matthias called Physics an “experimental journal”, which they hoped would solve the problem of there being “far more good physics written than any physicist can read”. Their solution was to pick only those papers worth the attention of all physicists, which the editors did by reviewing – then accepting or rejecting – every submission themselves. They even paid authors 10 cents a word if their paper appeared in print.

Anderson and Matthias admitted that many physicists had already written to them, criticizing their proposed selection model. They’d been told that their “judgements will be fallible”, that they might be “overimpressed by showiness”, and that they’d end up rejecting excellent work. In response, the pair promised to try their best, accepting they would make mistakes and that their “criteria will be, not better, but different”.

The journal’s criteria clearly succeeded, in that Anderson and Matthias identified the merits of Bell’s paper, which was far from mainstream
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These criteria clearly succeeded, in that they identified the merits of Bell’s paper, which was far from mainstream. Keen to find out more about the events surrounding its publication, I contacted Zangwill, who had interviewed Anderson several times for his book. Zangwill shared the following quote, published here for the first time.

“One day,” Anderson recalled, “a paper came in from a guy neither of us had heard of – John Bell. It was about hidden variables in quantum mechanics. Bernd had no clue, but I accepted it with the hope that its publication would spell the death of Bohmian trajectory quantum mechanics. It’s a very famous paper today.”

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In 1967 the quantum physicist John Clauser found Bell’s paper after stumbling upon Physics Physique Физика, attracted by its unusual title. Clauser, who shared the 2022 Nobel Prize in Physics, carried out the first Bell test in 1972 with Stuart Friedmann. Their work triggered a long series of experiments that would deepen our understanding of quantum mechanics and catalyse the development of quantum technologies.

Over its short life, Physics did publish work from other notable physicists including Murray Gell-Mann, Leonard Susskind and Leo Kadanoff. In fact, the journal was ahead of its time, with the model of in-house editorial selection for broad interest returning in the 2000s with the Nature series of journals. The inclusive, multi-language title was also well ahead of its day.

Sadly, Physics Physique Физика was discontinued in 1968 after just three volumes
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Sadly, Physics Physique Физика was discontinued in 1968 after just three volumes. According to what Anderson told Zangwill, it stopped “not because it lacked submissions, but because they had promised contributors rapid publication and Maxwell kept increasing the time between the appearances of successive issues”. Maxwell’s aggressive pursuit of profit might also have played a role.

The journal has since been archived by the American Physical Society and is freely accessible online. One can only wonder what might have happened if Anderson and Matthias had picked a different name for their journal.

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Studying the role of the quantum environment in attosecond science

Paul Mabey — Wed, 03 Dec 2025 10:00:03 +0000

Intrinsically disordered proteins (IDPs) do not form stable 3D structures. Instead, they remain flexible, adopt many conformations, and can interact with multiple molecules. Although proteins were once thought to require a fixed structure to function, many IDPs play essential cellular roles. Some IDPs can assemble into biomolecular condensates, membrane-less compartments that help organise processes such as gene expression and stress responses.

Many IDPs contain prion-like low complexity domains (PLCDs), which have defined sequence features known as molecular grammas. These IDPs are multivalent and can form hierarchies of interactions with one another. These interactions promote clustering and, under the right conditions, phase separation into a protein-rich condensate and a surrounding dilute phase. Dysregulation of condensates has been linked to disease.

In this study, researchers used computer simulations to investigate the PLCD known as A1-LCD. Their aims were to accurately identify the critical point where phase separation ceases, map the full phase diagram, and assess methods used to estimate the theta temperature (Tθ), a measure related to solvent quality and protein interactions.

The simulations revealed three distinct phase-separation regimes: a dilute phase containing mostly isolated proteins, an intermediate regime where clusters form before large condensates appear, and a regime near the critical point characterised by system-spanning networks. The study also showed that condensates behave as percolated networks of interconnected proteins. Importantly, the authors found that commonly used methods for estimating theta temperature may be inaccurate for these systems.

Overall, this work provides new insights into the phase behaviour of condensate-forming proteins and highlights the need for more reliable approaches to assessing solvent quality. These findings could improve future studies of biomolecular condensates and their roles in health and disease.

“Comparative assessments of driving forces for phase separation requires knowledge of IDP-specific critical points. Our application of rigorous finite size scaling methods pioneered by Kurt Binder helped us delineate the critical and mean field regimes and demonstrate how the critical point can be converged upon for realistic approximations of IDPs. This revealed several surprises regarding the complex nature of the coexisting dilute phase. Additionally, we found that calculation of the two-body interaction coefficient provides a computationally tractable approach to compute comparative, sequence-encoded driving forces for phase separation of IDPs. This is directly relevant to inferring how changes to molecular grammars influence phase behaviors driven by homotypic associations.” – Rohit V. Pappu, Washington University in St. Louis

Read the full article

Strong field physics in open quantum systems – IOPscience

N. Boroumand et al, 2025 Rep. Prog. Phys. 88 070501

Distinguishing near- versus off-critical phase behaviors of intrinsically disordered proteins

Gaurav Mitra et al 2026 Rep. Prog. Phys. 89 068101

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Biomolecular dynamics: order–disorder transitions and energy landscapes by Paul C Whitford, Karissa Y Sanbonmatsu and José N Onuchic (2012)

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Characterising quantum many-body states

Paul Mabey — Wed, 03 Dec 2025 09:59:45 +0000

According to band theory, materials with partially filled energy bands and unpaired electrons should conduct electricity, but in Mott insulators this rule is broken. In these materials, the repulsion between electrons is so strong that they cannot move freely and become localized. When sufficient energy is supplied (for example by light), electrons can form a doublon (two electrons on one site) and a hole (an empty site). These excitations can move, enabling electrical conductivity.

A key question for Mott insulators is how these charge carriers are created and what controls their production. Traditionally, two regimes were known: multiphoton absorption, where several photons combine their energy, and tunnelling, where a strong electric field drives electrons across the gap.

In this work, the authors show that there are actually four regimes: multiphoton, tunnelling, a cooperative regime where the two processes work together, and an incoherent regime where weak fields and scattering dominate. They also show that the energy gap (the cost to create a doubloon-hole pair) is not fixed, but changes during the process because the generated carriers modify the system. This creates a feedback loop, making the dynamics nonlinear and time-dependent. As a result, carrier production can either slow down or suddenly speed up, even making the system more efficient without changing the driving field.

The behaviour depends on field strength, frequency, dissipation, and time, and each mechanism can be identified by its distinct momentum pattern. By tuning laser parameters, the system’s properties can be controlled in real time. Overall, this work shows that light can be used to dynamically reshape and control strongly interacting materials, opening possibilities for ultrafast, light-driven technologies.

Read the full article

Many-body quantum resources of graph states – IOPscience

M. Płodzień et al, 2025 Rep. Prog. Phys. 88 077601

Subgap pumping of antiferromagnetic Mott insulators: photoexcitation mechanisms and applications

Radu Andrei et al 2026 Rep. Prog. Phys. 89 068004

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PLP-Logo-2.png, find out more. Quantum frustration in organic Mott insulators: from spin liquids to unconventional superconductors by B J Powell and Ross H McKenzie (2011)

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Extra carbon in the atmosphere may disrupt radio communications

Isabelle Dumé — Tue, 02 Dec 2025 14:13:19 +0000

Higher levels of carbon dioxide (CO₂) in the Earth’s atmosphere could harm radio communications by enhancing a disruptive effect in the ionosphere. According to researchers at Kyushu University, Japan, who modelled the effect numerically for the first time, this little-known consequence of climate change could have significant impacts on shortwave radio systems such as those employed in broadcasting, air traffic control and navigation.

“While increasing CO₂ levels in the atmosphere warm the Earth’s surface, they actually cool the ionosphere,” explains study leader Huixin Liu of Kyushu’s Faculty of Science. “This cooling doesn’t mean it is all good: it decreases the air density in the ionosphere and accelerates wind circulation. These changes affect the orbits and lifespan of satellites and space debris and also disrupt radio communications through localized small-scale plasma irregularities.”

The sporadic E-layer

One such irregularity is a dense but transient layer of metal ions that forms between 90‒120 km above the Earth’s surface. This sporadic E-layer (Es), as it is known, is roughly 1‒5 km thick and can stretch from tens to hundreds of kilometres in the horizontal direction. Its density is highest during the day, and it peaks around the time of the summer solstice.

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The formation of the Es is hard to predict, and the mechanisms behind it are not fully understood. However, the prevailing “wind shear” theory suggests that vertical shears in horizontal winds, combined with the Earth’s magnetic field, cause metallic ions such as Fe⁺, Na⁺ and Ca⁺ to converge in the ionospheric dynamo region and form thin layers of enhanced ionization. The ions themselves largely come from metals in meteoroids that enter the Earth’s atmosphere and disintegrate at altitudes of around 80‒100 km.

Effects of increasing CO₂concentrations

While previous research has shown that increases in CO₂ trigger atmospheric changes on a global scale, relatively little is known about how these increases affect smaller-scale ionospheric phenomena like the Es. In the new work, which is published in Geophysical Research Letters, Liu and colleagues used a whole-atmosphere model to simulate the upper atmosphere at two different CO₂ concentrations: 315 ppm and 667 ppm.

“The 315 ppm represents the CO₂ concentration in 1958, the year in which recordings started at the Mauna Loa observatory, Hawaii,” Liu explains. “The 667 ppm represents the projected CO₂ concentration for the year 2100, based on a conservative assumption that the increase in CO₂ is constant at a rate of around 2.5 ppm/year since 1958.”

The researchers then evaluated how these different CO₂levels influence a phenomenon known as vertical ion convergence (VIC) which, according to the wind shear theory, drives the Es. The simulations revealed that the higher the atmospheric CO₂ levels, the greater the VIC at altitudes of 100–120 km. “What is more, this increase is accompanied by the VIC hotspots shifting downwards by approximately 5 km,” says Liu. “The VIC patterns also change dramatically during the day and these diurnal variability patterns continue into the night.”

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According to the researchers, the physical mechanism underlying these changes depends on two factors. The first is reduced collisions between metallic ions and the neutral atmosphere as a direct result of cooling in the ionosphere. The second is changes in the zonal wind shear, which are likely caused by long-term trends in atmosphere tides.

“These results are exciting because they show that the impacts of CO₂ increase can extend all the way from Earth’s surface to altitudes at which HF and VHF radio waves propagate and communications satellites orbit,” Liu tells Physics World. “This may be good news for ham radio amateurs, as you will likely receive more signals from faraway countries more often. For radio communications, however, especially at HF and VHF frequencies employed for aviation, ships and rescue operations, it means more noise and frequent disruption in communication and hence safety. The telecommunications industry might therefore need to adjust their frequencies or facility design in the future.”

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Phase-changing material generates vivid tunable colours

Tami Freeman — Tue, 02 Dec 2025 12:00:32 +0000

Membership inference attack An untrusted user aims to infer whether a specific target record was part of the training dataset, by observing the predictions of a model. The attack is successful if they can reliably distinguish between models A and B, which are identical except for the inclusion or exclusion of the target record in the respective training dataset. (Courtesy: CC BY 4.0/Nature 10.1038/s41586-026-10688-0)

A new study has revealed that sensitive health information about individual patients can be extracted from medical artificial intelligence (AI) models more effectively than previous research had indicated.

Diagnostic AI models are used to determine whether some given health data belong to a specific class – for example if an X-ray image shows evidence of pneumonia – and offer huge promise for improving patient outcomes. Earlier studies showed that membership inference attacks (MIAs), which determine whether a particular person’s data was used to train an AI model, yielded results no better than random chance. But these previous studies only evaluated the average risk across all patients in a training dataset.

By contrast, in this latest work doctoral student Moritz Knolle and his supervisor Daniel Rückert at the Technical University of Munich (TUM), together with collaborators at Imperial College London and Georg Kaissis from the Hasso Plattner Institute (HPI), examined the privacy risk for an individual patient. “Privacy that only works on average has little meaning. So I asked myself: would I contribute my data to train a medical AI model?” says Knolle.

Investigating the risks A team led by Daniel Rückert (pictured) at TUM and Georg Kaissis from HPI found that medical AI is more vulnerable to certain attacks than previously thought. (Courtesy: Juli Eberle/TUM)

As detailed in their recent Nature paper, the researchers attacked AI models based on seven different types of real-life medical datasets, including one comprising 21,799 electrocardiograms and another of 377,110 chest radiographs.

“If a model sees a specific data point during training, it usually becomes more confident at predicting it. So in these MIA attacks I compare the predictive probability number for this data point outputted by the medical AI model with the predictive probability number obtained from my model which has not seen that data point,” explains Knolle, adding that the attack is essentially a statistical test to distinguish between the two models.

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Their results revealed that the privacy risk for an individual was far greater than the average risk. The team also found that privacy risk is not equally distributed among subgroups.

“We found that patients from minority groups that are under-represented in the training dataset tend to be over-represented among the 99 percentile of extreme [privacy] risk,” Knolle tells Physics World, warning that as medical AI models become larger and more sophisticated the privacy risk is amplified because their deep analysis creates the small changes in predictive probability that MIAs are good at finding.

While an MIA that reveals someone is a UK citizen poses little security risk, discovering that an individual has received a specific type of cancer treatment reveals personal information that could, for instance, adversely affect their medical insurance premiums. “The more specific the training cohort is, the larger the privacy risk,” states Knolle, crediting his medical doctor parents with inspiring his desire to improve healthcare AI.

Countermeasures include differential privacy (DP), in which a small amount of Gaussian random white noise is added in alongside the data during training, thereby reducing the effectiveness of MIAs while maintaining the model’s diagnostic accuracy. “This gives a mathematically provable upper bound for how much privacy risk any individual in this dataset could face, by limiting the information content that flows to the AI model,” explains Knolle.

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He notes that, unfortunately, such DP tools have not been widely adopted by hospitals or clinics. This, he fears, could undermine patients’ confidence in sharing their data, and thereby not only reduce AI’s ability to help combat rare diseases, but also compound AI discrimination that occurs when there is too little data from minority groups included in training datasets.

“So we are hoping to inspire the medical AI community to do risk assessments before deploying AI models, and use verifiable strategies such as DP or limiting access to the AI model, so that as an individual you have a statistical guarantee that no harm would come to you by being part of a dataset,” concludes Knolle, who now plans to investigate the privacy risks posed by generative AI models for healthcare.

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Semiconductor laser pioneer Susumu Noda wins 2026 Rank Prize for Optoelectronics

Michael Banks — Tue, 02 Dec 2025 09:00:41 +0000

Susumu Noda of Kyoto University has won the 2026 Rank Prize for Optoelectronics for the development of the Photonic Crystal Surface Emitting Laser (PCSEL). For more than 25 years, Noda developed this new form of laser, which has potential applications in high-precision manufacturing as well as in LIDAR technologies.

Following the development of the laser in 1960, in more recent decades optical fibre lasers and semiconductor lasers have become competing technologies.

A semiconductor laser works by pumping an electrical current into a region where an n-doped (excess of electrons) and a p-doped (excess of “holes”) semiconductor material meet, causing electrons and holes to combine and release photons.

Semiconductors have several advantages in terms of their compactness, high “wallplug” efficiency, and ruggedness, but lack in other areas such as having a low brightness and functionality.

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This means that conventional semiconductor lasers required external optical and mechanical elements to improve their performance, which results in large and impractical systems.

‘A great honour’

In the late 1990s, Noda began working on a new type of semiconductor laser that could challenge the performance of optical fibre lasers. These so-called PCSELs employ a photonic crystal layer in between the semiconductor layers. Photonic crystals are nanostructured materials in which a periodic variation of the dielectric constant — formed, for example, by a lattice of holes — creates a photonic band-gap.

Noda and his research made a series of breakthrough in the technology such as demonstrating control of polarization and beam shape by tailoring the phonic crystal structure and expansion into blue–violet wavelengths.

The resulting PCSELs emit a high-quality, symmetric beam with narrow divergence and boast high brightness and high functionality while maintaining the benefits of conventional semiconductor lasers. In 2013, 0.2 W PCSELs became available and a few years later Watt-class PCSEL lasers became operational.

Noda says that it is “a great honour and a surprise” to receive the prize. “I am extremely happy to know that more than 25 years of research on photonic-crystal surface-emitting lasers has been recognized in this way,” he adds. “I do hope to continue to further develop the research and its social implementation.”

Susumu Noda received his BSc and then PhD in electronics from Kyoto University in 1982 and 1991, respectively. From 1984 he also worked at Mitsubishi Electric Corporation, before joining Kyoto University in 1988 where he is currently based.

Founded in 1972 by the British industrialist and philanthropist Lord J Arthur Rank, the Rank Prize is awarded biennially in nutrition and optoelectronics. The 2026 Rank Prize for Optoelectronics, which has a cash award of £100 000, will be awarded formally at an event held in June.

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Staying the course with lockdowns could end future pandemics in months

No Author — Mon, 01 Dec 2025 14:00:32 +0000

As a theoretical and mathematical physicist at Imperial College London, UK, Bhavin Khatri spent years using statistical physics to understand how organisms evolve. Then the COVID-19 pandemic struck, and like many other scientists, he began searching for ways to apply his skills to the crisis. This led him to realize that the equations he was using to study evolution could be repurposed to model the spread of the virus – and, crucially, to understand how it could be curtailed.

In a paper published in EPL, Khatri models the spread of a SARS-CoV-2-like virus using branching process theory, which he’d previously used to study how advantageous alleles (variations in a genetic sequence) become more prevalent in a population. He then uses this model to assess the duration that interventions such as lockdowns would need to be applied in order to completely eliminate infections, with the strength of the intervention measured in terms of the number of people each infected person goes on to infect (the virus’ effective reproduction number, R).

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Tantalizingly, the paper concludes that applying such interventions worldwide in June 2020 could have eliminated the COVID virus by January 2021, several months before the widespread availability of vaccines reduced its impact on healthcare systems and led governments to lift restrictions on social contact. Physics World spoke to Khatri to learn more about his research and its implications for future pandemics.

What are the most important findings in your work?

One important finding is that we can accurately calculate the distribution of times required for a virus to become extinct by making a relatively simple approximation. This approximation amounts to assuming that people have relatively little population-level “herd” immunity to the virus – exactly the situation that many countries, including the UK, faced in March 2020.

Making this approximation meant I could reduce the three coupled differential equations of the well-known SIR model (which models pandemics via the interplay between Susceptible, Infected and Recovered individuals) to a single differential equation for the number of infected individuals in the population. This single equation turned out to be the same one that physics students learn when studying radioactive decay. I then used the discrete stochastic version of exponential decay and standard approaches in branching process theory to calculate the distribution of extinction times.

Simulation trajectories a) A plot of the decline in the number of infected individuals over time. b) Probability density of extinction times for the same parameters as in a), showing that the most likely extinction times are measured in months. (Courtesy: Bhavin S. Khatri 2025 EPL 152 11003 DOI 10.1209/0295-5075/ae0c31 CC-BY 4.0 https://creativecommons.org/licenses/by/4.0/)

Alongside the formal theory, I also used my experience in population genetic theory to develop an intuitive approach for calculating the mean of this extinction time distribution. In population genetics, when a mutation is sufficiently rare, changes in its number of copies in the population are dominated by randomness. This is true even if the mutation has a large selective advantage: it has to grow by chance to sufficient critical size – on the order of 1/(selection strength) – for selection to take hold.

The same logic works in reverse when applied to a declining number of infections. Initially, they will decline deterministically, but once they go below a threshold number of individuals, changes in infection numbers become random. Using the properties of such random walks, I calculated an expression for the threshold number and the mean duration of the stochastic phase. These agree well with the formal branching process calculation.

In practical terms, the main result of this theoretical work is to show that for sufficiently strong lockdowns (where, on average, only one of every two infected individuals goes on to infect another person, R=0.5), this distribution of extinction times was narrow enough to ensure that the COVID pandemic virus would have gone extinct in a matter of months, or at most a year.

How realistic is this counterfactual scenario of eliminating SARS-CoV-2 within a year?

Leaving politics and the likelihood of social acceptance aside for the moment, if a sufficiently strong lockdown could have been maintained for a period of roughly six months across the globe, then I am confident that the virus could have been reduced to very low levels, or even made extinct.

The question then is: is this a stable situation? From the perspective of a single nation, if the rest of the world still has infections, then that nation either needs to maintain its lockdown or be prepared to re-impose it if there are new imported cases. From a global perspective, a COVID-free world should be a stable state, unless an animal reservoir of infections causes re-infections in humans.

Modelling the decline of a virus: Theoretical physicist and biologist Bhavin Khatri. (Courtesy: Bhavin Khatri)

As for the practical success of such a strategy, that depends on politics and the willingness of individuals to remain in lockdown. Clearly, this is not in the model. One thing I do discuss, though, is that this strategy becomes far more difficult once more infectious variants of SARS-CoV-2 evolve. However, the problem I was working on before this one (which I eventually published in PNAS) concerned the probability of evolutionary rescue or resistance, and that work suggests that evolution of new COVID variants reduces significantly when there are fewer infections. So an elimination strategy should also be more robust against the evolution of new variants.

What lessons would you like experts (and the public) to take from this work when considering future pandemic scenarios?

I’d like them to conclude that pandemics with similar properties are, in principle, controllable to small levels of infection – or complete extinction – on timescales of months, not years, and that controlling them minimizes the chance of new variants evolving. So, although the question of the political and social will to enact such an elimination strategy is not in the scope of the paper, I think if epidemiologists, policy experts, politicians and the public understood that lockdowns have a finite time horizon, then it is more likely that this strategy could be adopted in the future.

I should also say that my work makes no comment on the social harms of lockdowns, which shouldn’t be minimized and would need to be weighed against the potential benefits.

What do you plan to do next?

I think the most interesting next avenue will be to develop theory that lets us better understand the stability of the extinct state at the national and global level, under various assumptions about declining infections in other countries that adopted different strategies and the role of an animal reservoir.

It would also be interesting to explore the role of “superspreaders”, or infected individuals who infect many other people. There’s evidence that many infections spread primarily through relatively few superspreaders, and heuristic arguments suggest that taking this into account would decrease the time to extinction compared to the estimates in this paper.

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I’ve also had a long-term interest in understanding the evolution of viruses from the lens of what are known as genotype phenotype maps, where we consider the non-trivial and often redundant mapping from genetic sequences to function, where the role of stochasticity in evolution can be described by statistical physics analogies. For the evolution of the antibodies that help us avoid virus antigens, this would be a driven system, and theories of non-equilibrium statistical physics could play a role in answering questions about the evolution of new variants.

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When is good enough ‘good enough’?

Honor Powrie — Mon, 01 Dec 2025 11:00:21 +0000

Whether you’re running a business project, carrying out scientific research, or doing a spot of DIY around the house, knowing when something is “good enough” can be a tough question to answer. To me, “good enough” means something that is fit for purpose. It’s about striking a balance between the effort required to achieve perfection and the cost of not moving forward. It’s an essential mindset when perfection is either not needed or – as is often the case – not attainable.

When striving for good enough, the important thing to focus on is that your outcome should meet expectations, but not massively exceed them. Sounds simple, but how often have we heard people say things like they’re “polishing coal”, striving for “gold plated” or “trying to make a silk purse out of a sow’s ear”. It basically means they haven’t understood, defined or even accepted the requirements of the end goal.

Trouble is, as we go through school, college and university, we’re brought up to believe that we should strive for the best in whatever we study. Those with the highest grades, we’re told, will probably get the best opportunities and career openings. Unfortunately, this approach means we think we need to aim for perfection in everything in life, which is not always a good thing.

How to be good enough

So why is aiming for “good enough” a good thing to do? First, there’s the notion of “diminishing returns”. It takes a disproportionate amount of effort to achieve the final, small improvements that most people won’t even notice. Put simply, time can be wasted on unnecessary refinements, as embodied by the 80/20 rule (see box).

The 80/20 rule: the guiding principle of “good enough”

Also known as the Pareto principle – in honour of the Italian economist Vilfredo Pareto who first came up with the idea – the 80/20 rule states that for many outcomes, 80% of consequences or results come from 20% of the causes or effort. The principle helps to identify where to prioritize activities to boost productivity and get better results. It is a guideline, and the ratios can vary, but it can be applied to many things in both our professional and personal lives.

Examples from the world of business include the following:

Business sales: 80% of a company’s revenue might come from 20% of its customers.

Company productivity: 80% of your results may come from 20% of your daily tasks.

Software development: 80% of bugs could be caused by 20% of the code.

Quality control: 20% of defects may cause 80% of customer complaints.

Good enough also helps us to focus efforts. When a consumer or customer doesn’t know exactly what they want, or a product development route is uncertain, it can be better to deliver things in small chunks. Providing something basic but usable can be used to solicit feedback to help clarify requirements or make improvements or additions that can be incorporated into the next chunk. This is broadly along the lines of a “minimum viable product”.

Not seeking perfection reminds us too that solutions to problems are often uncertain. If it’s not clear how, or even if, something might work, a proof of concept (PoC) can instead be a good way to try something out. Progress can be made by solving a specific technical challenge, whether via a basic experiment, demonstration or short piece of research. A PoC should help avoid committing significant time and resource to something that will never work.

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Aiming for “good enough” naturally leads us to the notion of “continuous improvement”. It’s a personal favourite of mine because it allows for things to be improved incrementally as we learn or get feedback, rather than producing something in one go and then forgetting about it. It helps keep things current and relevant and encourages a culture of constantly looking for a better way to do things.

Finally, when searching for good enough, don’t forget the idea of ballpark estimates. Making approximations sounds too simple to be effective, but sometimes a rough estimate is really all you need. If an approximate guess can inform and guide your next steps or determine whether further action will be necessary then go for it.

The benefits of good enough

Being good enough doesn’t just lead to practical outcomes, it can benefit our personal well-being too. Our time, after all, is a precious commodity and we can’t magically increase this resource. The pursuit of perfection can lead to stagnation, and ultimately burnout, whereas achieving good enough allows us to move on in a timely fashion.

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A good-enough approach will even make you less stressed. By getting things done sooner and achieving more, you’ll feel freer and happier about your work even if it means accepting imperfection. Mistakes and errors are inevitable in life, so don’t be afraid to make them; use them as learning opportunities, rather than seeing them as something bad. Remember – the person who never made a mistake never got out of bed.

Recognizing that you’ve done the best you can for now is also crucial for starting new projects and making progress. By accepting good enough you can build momentum, get more things done, and consistently take actions toward achieving your goals.

Finally, good enough is also about shared ownership. By inviting someone else to look at what you’ve done, you can significantly speed up the process. In my own career I’ve often found myself agonising over some obscure detail or feeling something is missing, only to have my quandary solved almost instantly simply by getting someone else involved – making me wish I’d asked them sooner.

Caveats and conclusions

Good enough comes with some caveats. Regulatory or legislative requirements means there will always be projects that have to reach a minimum standard, which will be your top priority. The precise nature of good enough will also depend on whether you’re making stuff (be it cars or computers) or dealing with intangible commodities such as software or services.

So what’s the conclusion? Well, in the interests of my own time, I’ve decided to apply the 80/20 rule and leave it to you to draw your own conclusion. As far as I’m concerned, I think this article has been good enough, but I’m sure you’ll let me know if it hasn’t. Consider it as a minimally viable product that I can update in a future column.

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Looking for inconsistencies in the fine structure constant

Isabelle Dumé — Mon, 01 Dec 2025 09:06:19 +0000

The core element of the experiment: a crystal containing thorium atoms. (Courtesy: TU Wien)

New high-precision laser spectroscopy measurements on thorium-229 nuclei could shed more light on the fine structure constant, which determines the strength of the electromagnetic interaction, say physicists at TU Wien in Austria.

The electromagnetic interaction is one of the four known fundamental forces in nature, with the others being gravity and the strong and weak nuclear forces. Each of these fundamental forces has an interaction constant that describes its strength in comparison with the others. The fine structure constant, α, has a value of approximately 1/137. If it had any other value, charged particles would behave differently, chemical bonding would manifest in another way and light-matter interactions as we know them would not be the same.

“As the name ‘constant’ implies, we assume that these forces are universal and have the same values at all times and everywhere in the universe,” explains study leader Thorsten Schumm from the Institute of Atomic and Subatomic Physics at TU Wien. “However, many modern theories, especially those concerning the nature of dark matter, predict small and slow fluctuations in these constants. Demonstrating a non-constant fine-structure constant would shatter our current understanding of nature, but to do this, we need to be able to measure changes in this constant with extreme precision.”

With thorium spectroscopy, he says, we now have a very sensitive tool to search for such variations.

Nucleus becomes slightly more elliptic

The new work builds on a project that led, last year, to the worlds’s first nuclear clock, and is based on precisely determining how the thorium-229 (²²⁹Th) nucleus changes shape when one of its neutrons transitions from a ground state to a higher-energy state. “When excited, the ²²⁹Th nucleus becomes slightly more elliptic,” Schumm explains. “Although this shape change is small (at the 2% level), it dramatically shifts the contributions of the Coulomb interactions (the repulsion between protons in the nucleus) to the nuclear quantum states.”

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The result is a change in the geometry of the ²²⁹Th nucleus’ electric field, to a degree that depends very sensitively on the value of the fine structure constant. By precisely observing this thorium transition, it is therefore possible to measure whether the fine-structure constant is actually a constant or whether it varies slightly.

After making crystals of ²²⁹Th doped in a CaF₂ matrix at TU Wien, the researchers performed the next phase of the experiment in a JILA laboratory at the University of Colorado, Boulder, US, firing ultrashort laser pulses at the crystals. While they did not measure any changes in the fine structure constant, they did succeed in determining how such changes, if they exist, would translate into modifications to the energy of the first nuclear excited state of ²²⁹Th.

“It turns out that this change is huge, a factor 6000 larger than in any atomic or molecular system, thanks to the high energy governing the processes inside nuclei,” Schumm says. “This means that we are by a factor of 6000 more sensitive to fine structure variations than previous measurements.”

Increasing the spectroscopic accuracy of the ²²⁹Th transition

Researchers in the field have debated the likelihood of such an “enhancement factor” for decades, and theoretical predictions of its value have varied between zero and 10 000. “Having confirmed such a high enhancement factor will now allow us to trigger a ‘hunt’ for the observation of fine structure variations using our approach,” Schumm says.

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Andrea Caputo of CERN’s theoretical physics department, who was not involved in this work, calls the experimental result “truly remarkable”, as it probes nuclear structure with a precision that has never been achieved before. However, he adds that the theoretical framework is still lacking. “In a recent work published shortly before this work, my collaborators and I showed that the nuclear-clock enhancement factor K is still subject to substantial theoretical uncertainties,” Caputo says. “Much progress is therefore still required on the theory side to model the nuclear structure reliably.”

Schumm and colleagues are now working on increasing the spectroscopic accuracy of their ²²⁹Th transition measurement by another one to two orders of magnitude. “We will then start hunting for fluctuations in the transition energy,” he reveals, “tracing it over time and – through the Earth’s movement around the Sun – space.

The present work is detailed in Nature Communications.

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Heat engine captures energy as Earth cools at night

No Author — Fri, 28 Nov 2025 14:45:22 +0000

A new heat engine driven by the temperature difference between Earth’s surface and outer space has been developed by Tristan Deppe and Jeremy Munday at the University of California Davis. In an outdoor trial, the duo showed how their engine could offer a reliable source of renewable energy at night.

While solar cells do a great job of converting the Sun’s energy into electricity, they have one major drawback, as Munday explains: “Lack of power generation at night means that we either need storage, which is expensive, or other forms of energy, which often come from fossil fuel sources.”

One solution is to exploit the fact that the Earth’s surface absorbs heat from the Sun during the day and then radiates some of that energy into space at night. While space has a temperature of around −270° C, the average temperature of Earth’s surface is a balmy 15° C. Together, these two heat reservoirs provide the essential ingredients of a heat engine, which is a device that extracts mechanical work as thermal energy flows from a heat source to a heat sink.

Coupling to space

“At first glance, these two entities appear too far apart to be connected through an engine. However, by radiatively coupling one side of the engine to space, we can achieve the needed temperature difference to drive the engine,” Munday explains.

For the concept to work, the engine must radiate the energy it extracts from the Earth within the atmospheric transparency window. This is a narrow band of infrared wavelengths that pass directly into outer space without being absorbed by the atmosphere.

To demonstrate this concept, Deppe and Munday created a Stirling engine, which operates through the cyclical expansion and contraction of an enclosed gas as it moves between hot and cold ends. In their setup, the ends were aligned vertically, with a pair of plates connecting each end to the corresponding heat reservoir.

For the hot end, an aluminium mount was pressed into soil, transferring the Earth’s ambient heat to the engine’s bottom plate. At the cold end, the researchers attached a black-coated plate that emitted an upward stream of infrared radiation within the transparency window.

Outdoor experiments

In a series of outdoor experiments performed throughout the year, this setup maintained a temperature difference greater than 10° C between the two plates during most months. This was enough to extract more than 400 mW per square metre of mechanical power throughout the night.

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“We were able to generate enough power to run a mechanical fan, which could be used for air circulation in greenhouses or residential buildings,” Munday describes. “We also configured the device to produce both mechanical and electrical power simultaneously, which adds to the flexibility of its operation.”

With this promising early demonstration, the researchers now predict that future improvements could enable the system to extract as much as 6 W per square metre under the same conditions. If rolled out commercially, the heat engine could help reduce the reliance of solar power on night-time energy storage – potentially opening a new route to cutting carbon emissions.

The research has described in Science Advances.

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Microscale ‘wave-on-a-chip’ device sheds light on nonlinear hydrodynamics

Isabelle Dumé — Fri, 28 Nov 2025 09:40:36 +0000

A new microscale version of the flumes that are commonly used to reproduce wave behaviour in the laboratory will make it far easier to study nonlinear hydrodynamics. The device consists of a layer of superfluid helium just a few atoms thick on a silicon chip, and its developers at the University of Queensland, Australia, say it could help us better understand phenomena ranging from oceans and hurricanes to weather and climate.

“The physics of nonlinear hydrodynamics is extremely hard to model because of instabilities that ultimately grow into turbulence,” explains study leader Warwick Bowen of Queensland’s Quantum Optics Laboratory. “It is also very hard to study in experiments since these often require hundreds-of-metre-long wave flumes.”

While such flumes are good for studying shallow-water dynamics like tsunamis and rogue waves, Bowen notes that they struggle to access many of the complex wave behaviours, such as turbulence, found in nature.

Amplifying the nonlinearities in complex behaviours

The team say that the geometrical structure of the new wave-on-a-chip device can be designed at will using lithographic techniques and built in a matter of days. Superfluid helium placed on its surface can then be controlled optomechanically. Thanks to these innovations, the researchers were able to experimentally measure nonlinear hydrodynamics millions of times faster than would be possible using traditional flumes. They could also “amplify” the nonlinearities of complex behaviours, making them orders of magnitude stronger than is possible in even the largest wave flumes.

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“This promises to change the way we do nonlinear hydrodynamics, with the potential to discover new equations that better explain the complex physics behind it,” Bowen says. “Such a technique could be used widely to improve our ability to predict both natural and engineered hydrodynamic behaviours.”

So far, the team has measured several effects, including wave steepening, shock fronts and solitary wave fission thanks to the chip. While these nonlinear behaviours had been predicted in superfluids, they had never been directly observed there until now.

Waves can be generated in a very shallow depth

The Quantum Optics Laboratory researchers have been studying superfluid helium for over a decade. A key feature of this quantum liquid is that it flows without resistance, similar to the way electrons move without resistance in a superconductor. “We realized that this behaviour could be exploited in experimental studies of nonlinear hydrodynamics because it allows waves to be generated in a very shallow depth – even down to just a few atoms deep,” Bowen explains.

In conventional fluids, Bowen continues, resistance to motion becomes hugely important at small scales, and ultimately limits the nonlinear strengths accessible in traditional flume-based testing rigs. “Moving from the tens-of-centimetre depths of these flumes to tens-of-nanometres, we realized that superfluid helium could allow us to achieve many orders of magnitude stronger nonlinearities – comparable to the largest flows in the ocean – while also greatly increasing measurement speeds. It was this potential that attracted us to the project.”

The experiments were far from simple, however. To do them, the researchers needed to cryogenically cool the system to near absolute zero temperatures. They also needed to fabricate exceptionally thin superfluid helium films that interact very weakly with light, as well as optical devices with structures smaller than a micron. Combining all these components required what Bowen describes as “something of a hero experiment”, with important contributions coming from the team’s co-leader, Christopher Baker, and Walter Wasserman, who was then a PhD student in the group. The wave dynamics themselves, Bowen adds, were “exceptionally complex” and were analysed by Matthew Reeves, the first author of a Science paper describing the device.

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As well as the applications areas mentioned earlier, the team say the new work, which is supported by the US Defense Advanced Research Project Agency’s APAQuS Program, could also advance our understanding of strongly-interacting quantum structures that are difficult to model theoretically. “Superfluid helium is a classic example of such a system,” explains Bowen, “and our measurements represent the most precise measurements of wave physics in these. Other applications may be found in quantum technologies, where the flow of superfluid helium could – somewhat speculatively – replace superconducting electron flow in future quantum computing architectures.”

The researchers now plan to use the device and machine learning techniques to search for new hydrodynamics equations.

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Electrical charge on objects in optical tweezers can be controlled precisely

No Author — Thu, 27 Nov 2025 16:21:23 +0000

An effect first observed decades ago by Nobel laureate Arthur Ashkin has been used to fine tune the electrical charge on objects held in optical tweezers. Developed by an international team led by Scott Waitukaitis of the Institute of Science and Technology Austria, the new technique could improve our understanding of aerosols and clouds.

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Optical tweezers use focused laser beams to trap and manipulate small objects about 100 nm to 1 micron in size. Their precision and versatility have made them a staple across fields from quantum optics to biochemistry.

Ashkin shared the 2018 Nobel prize for inventing optical tweezers and in the 1970s he noticed that trapped objects can be electrically charged by the laser light. “However, his paper didn’t get much attention, and the observation has essentially gone ignored,” explains Waitukaitis.

Waitukaitis’ team rediscovered the effect while using optical tweezers to study how charges build up in the ice crystals accumulating inside clouds. In their experiment, micron-sized silica spheres stood in for the ice, but Ashkin’s charging effect got in their way.

Bummed out

“Our goal has always been to study charged particles in air in the context of atmospheric physics – in lightning initiation or aerosols, for example,” Waitukaitis recalls. “We never intended for the laser to charge the particle, and at first we were a bit bummed out that it did so.”

Their next thought was that they had discovered a new and potentially useful phenomenon. “Out of due diligence we of course did a deep dive into the literature to be sure that no one had seen it, and that’s when we found the old paper from Ashkin, “ says Waitukaitis.

In 1976, Ashkin described how optically trapped objects become charged through a nonlinear process whereby electrons absorb two photons simultaneously. These electrons can acquire enough energy to escape the object, leaving it with a positive charge.

Yet beyond this insight, Ashkin “wasn’t able to make much sense of the effect,” Waitukaitis explains. “I have the feeling he found it an interesting curiosity and then moved on.”

Shaking and scattering

To study the effect in more detail, the team modified their optical tweezers setup so its two copper lens holders doubled as electrodes, allowing them to apply an electric field along the axis of the confining, opposite-facing laser beams. If the silica sphere became charged, this field would cause it to shake, scattering a portion of the laser light back towards each lens.

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The researchers picked off this portion of the scattered light using a beam splitter, then diverted it to a photodiode, allowing them to track the sphere’s position. Finally, they converted the measured amplitude of the shaking particle into a real-time charge measurement. This allowed them to track the relationship between the sphere’s charge and the laser’s tuneable intensity.

Their measurements confirmed Ashkin’s 1976 hypothesis that electrons on optically-trapped objects undergo two-photon absorption, allowing them to escape. Waitukaitis and colleagues improved on this model and showed how the charge on a trapped object can be controlled precisely by simply adjusting the laser’s intensity.

As for the team’s original research goal, the effect has actually been very useful for studying the behaviour of charged aerosols.

“We can get [an object] so charged that it shoots off little ‘microdischarges’ from its surface due to breakdown of the air around it, involving just a few or tens of electron charges at a time,” Waitukaitis says. “This is going to be really cool for studying electrostatic phenomena in the context of particles in the atmosphere.“

The study is described in Physical Review Letters.

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Quantum gravity: we explore spin foams and other potential solutions to this enduring challenge

Hamish Johnston — Thu, 27 Nov 2025 15:00:43 +0000

Earlier this autumn I had the pleasure of visiting the Perimeter Institute for Theoretical Physics in Waterloo Canada – where I interviewed four physicists about their research. This is the second of those conversations to appear on the podcast – and it is with Bianca Dittrich, whose research focuses on quantum gravity.

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Albert Einstein’s general theory of relativity does a great job at explaining gravity but it is thought to be incomplete because it is incompatible with quantum mechanics. This is an important shortcoming because quantum mechanics is widely considered to be one of science’s most successful theories.

Developing a theory of quantum gravity is a crucial goal in physics, but it is proving to be extremely difficult. In this episode, Dittrich explains some of the challenges and talks about ways forward – including her current research on spin foams. We also chat about the intersection of quantum gravity and condensed matter physics; and the difficulties of testing theories against observational data.

The first interview in this series from the PI was with Javier Toledo-Marín: “Quantum computing and AI join forces for particle physics”

IOP Publishing’s new Progress In Series: Research Highlights website offers quick, accessible summaries of top papers from leading journals like Reports on Progress in Physics and Progress in Energy. Whether you’re short on time or just want the essentials, these highlights help you expand your knowledge of leading topics.

The post Quantum gravity: we explore spin foams and other potential solutions to this enduring challenge appeared first on Physics World.

Environmental Research: Climate was launched in 2022, with the aim of uniting multidisciplinary communities. With a scope that is intentionally broad, the mission of the journal is to publish innovative research examining the causes, consequences, and solutions of climate variability and change. Since our launch, we have published more than 270 articles covering physical and biogeochemical processes that shape Earth’s climate across spatial and temporal scales; the human and ecological dimensions that shape climate-related risks and impacts; and the design, analysis and evaluation of climate mitigation, adaptation, and risk-management strategies and solutions. This webinar will explore the current state of climate research, including changes in the field over the last five years since the launch of the journal, and direct us toward the future.

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Left to right: Noah Diffenbaugh, Katharine Mach, Andrew Pershing, Inês Azevedo

Moderator: Noah Diffenbaugh, Stanford University
+Noah Diffenbaugh is the William Wrigley Professor and Kimmelman Family Senior Fellow in Stanford’s Doerr School of Sustainability, and the Olivier Nomellini Family University Fellow in Undergraduate Education. His research is focused on understanding what aspects of the climate system most directly and acutely impact people and ecosystems. Noah has served as a Lead Author for the Intergovernmental Panel on Climate Change (IPCC), and as editor-in-chief of the peer-review journals Geophysical Research Letters and Environmental Research: Climate. He has provided testimony and scientific expertise to federal, state and local officials. Noah is an elected Fellow of the American Geophysical Union (AGU), a recipient of the James R. Holton Award and William Kaula Award from the AGU, and has been recognized as a Kavli Fellow by the U.S. National Academy of Sciences.

Katharine Mach, University of Miami
+Katharine Mach is professor and chair of the Department of Environmental Science and Policy at the University of Miami Rosenstiel School of Marine, Atmospheric, & Earth Science. During spring 2025, she was the Coleman P. Burke Distinguished Visiting Professor at the Yale School of Environment. Her research assesses climate-related risks and response options to address increased flooding, extreme heat, wildfire and other hazards. Through innovative approaches to integrating evidence, she informs effective adaptations to the risks.

Katharine was the 2020 recipient of the Piers Sellers Prize for world-leading contribution to solution-focused climate research. She has served as a chapter author or lead in the Fourth through Sixth US National Climate Assessments and the IPCC Sixth Assessment Report and as a member of the National Academies Climate Security Roundtable. She serves as co-editor-in-chief for Climate Risk Management, an editorial board member for Oxford Open Climate Change and Environmental Research: Climate, and an advisory committee member for the Aspen Global Change Institute. Across all of her research projects, she engages in relevant policy processes and explores and discusses climate risk and adaptation with the media, the private sector, nongovernmental organizations and communities.

Andrew Pershing, Climate Central
+As chief programme officer, Andrew Pershing, PhD, leads Climate Central’s climate science activity. His role includes bridging primary research and media analysis to amplify critical work on climate change and climate impacts and make it accessible to audiences around the world. As the director of attribution science and climate fingerprinting, Andrew is developing tools like the Climate Shift Index to quantify how climate change has increased the likelihood or severity of conditions in the atmosphere and ocean. He works closely with communications experts at Climate Central and our partners to help the media and others to incorporate this information into their content.

Andrew has led interdisciplinary research teams to study the impact of global warming on marine ecosystems in the northwest Atlantic. More recently, his work has focused on how climate trends interact with decisions that people make and on how marine ecosystems store and process carbon. As a communicator, Andrew has deep experience working with journalists to present climate science on air and in print.

Inês Azevedo, Stanford University
+Inês M Lima Azevedo is a professor in the Energy Science & Engineering department at Stanford University. She is a senior fellow at both Stanford Woods Institute for the Environment and for Precourt Institute for Energy. She has a BSc in environmental engineering (2004) and a MSc in engineering policy and management of technology from IST-Portugal, and a PhD in engineering and public policy from Carnegie Mellon University (2009). Inês is passionate about solving problems that include environmental, technical, economic and policy issues, where traditional engineering approaches play an important role but cannot provide a complete answer. In particular, she is interested in assessing how energy systems are likely to evolve, which requires comprehensive knowledge of the technologies that can address future energy needs and the decision-making process followed by various agents in the economy.

About this journal
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Environmental Research: Climate explores the causes, consequences, and solutions of climate variability and change, by uniting research communities across the entire spectrum of the climate system.

Editor-in-chief: Noah Diffenbaugh Stanford University, USA

The post Environmental Research: Climate, fireside chat appeared first on Physics World.

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